Effect of explosive mixture on quality of explosive welds of copper to aluminium

The aim of this research is to investigate the influence of explosive ratio and type of sensitizer on the quality of explosive welds between copper and aluminium alloy plates. The welds were performed on a partially overlapping joint configuration using an emulsion explosive (EE) with two different sensitizers, hollow glass microspheres (HGMS) and expanded polystyrene spheres (EPS). Welds with an improved surface were achieved by using the HGMS sensitizer. A higher wave amplitude was registered in welds produced with the EPS sensitizer. In turn, the dimension of the molten pockets was influenced by the explosive ratio, increasing in size with increases in the values of this parameter. The intermetallic content of these zones varied according to the sensitizer type. Unlike the CuAl2 phase, the Cu-richer phases CuAl and Cu9Al4 were only identified in welds performed using the EPS sensitizer. An increase in hardness was observed at the interface of all welds, which resulted from both the presence of intermetallic phases and the plastic deformation of the materials promoted by the impact. This effect was most evident on the aluminium alloy side. All the welds had a greater strength than copper, i.e. the weakest material of the joint. (C) 2016 Elsevier Ltd. All rights reserved.

Serum copper evolution in patients that underwent endoscopic gastrostomy for long term enteral feeding

Background and aims: Copper (Cu) is a well studied trace element but little is known about Cu evolution in long term endoscopic gastrostomy (PEG) feeding. We aimed to evaluate the evolution serum Cu since the gastrostomy until 12 weeks after the procedure in PEG patients fed with homemade meals. Methods: A prospective observational study was performed evaluating serum copper, albumin, transferrin and body mass index (BMI) at the time of the gastrostomy, 4 weeks and 12 weeks after. Data also included age, gender, NRS 2002 and nature of the underlying disease causing dysphagia: head and neck cancer (HNC) or neurological dysphagia (ND). After gastrostomy, patients were fed with homemade PEG meals. Results: One hundred and forty-six patients enrolled, 89 men, aged 21-95 years, 90 with neurologic dysphagia (ND), and 56 with head and neck cancer (HNC). 78 (53%) showed low BMI. Initially, Cu ranged 42-160 μg/dl (normal: 70-140 μg/dl); 130 patients (89%) presented normal Cu, 16 (11%) presented hypocupremia, 53% low albumin (n = 77), and 94 (65%) low transferrin. After 4 weeks, 93% presented normal Cu, 7% presented hypocupremia, low albumin was present in 34%, and low transferrin in 52%. After 12 weeks, 95% presented normal Cu, 5% presented hypocupremia, low albumin was present in 25%, and low transferrin in 32%. Comparing age, gender, underlying disease, BMI, albumin and transferrin, there were no significant differences on serum Cu. Conclusions: Most patients present normal serum Cu when gastrostomy is performed. For patients presenting hypocupremia before gastrostomy, homemade meals are effective for normalizing serum Cu.