Effect of process parameters on the physical characteristics of spot weld joints

International audienceThis work deals with the study of the welding resistance using a technique based on spot welding. The effect of process parameters (arc intensity, welding duration and applied load) are pointed out by considering the physical characteristics of the weld joints. A tensile test permitted to determine experimentally the variations of the Young's modulus, elongation at break and the tensile strength associated to the process parameters. A statistical analysis of the experimental data permitted to point out the large sensitivity of Young's modulus to the process parameters, especially the applied load. The other characteristics seem to be less sensitive to the are intensity. The analysis of the coupled effects by considering 3D characteristic maps permitted to conclude on a small interaction between arc current and welding duration whereas the applied load was the control factor. (c) 2005 Elsevier Ltd. All rights reserved

Outbreak of extended spectrum beta-lactamase-producing Klebsiella pneumoniae in an intensive care unit (Brest). [Épidémie à Klebsiella pneumoniae productrice de bêta-lactamase à spectre étendu dans deux services de réanimation (Brest)]

International audienceINTRODUCTION: We had for aim to describe control and investigation of an outbreak caused by a strain of Extended spectrum beta-lactamase producing Klebsiella pneumoniae in intensive care units of the Brest teaching hospital. PATIENTS AND METHOD: The case definition was a patient infected by or carrying the epidemic strain. Control measures and investigations are presented. A case-control study was conducted in the surgical intensive care unit. Each case was matched with two controls based on admission times in the unit. The study focused on diagnostic and therapeutic procedures, and potential contacts with healthcare workers, in this context of cross transmission. RESULTS: Between February and May 2011, nine cases were reported in the surgical ICU and two in the medical ICU. Eighteen controls were matched with the nine surgical ICU cases. Several factors were found to be statistically associated with infection or colonization by the epidemic strain: the surgical block in which patients had been operated and the ward of first hospitalization; the number of trans-esophageal and trans-thoracic echocardiographies, of central venous catheter insertions, and of surgical operations; intubation. The total number of invasive procedures was also found to be statistically higher among cases. CONCLUSION: This study identified factors associated with colonization or infection by the epidemic strain. These factors might have been involved in the transmission tree, and be vulnerable elements for the prevention of nosocomial infections and colonisations, and their epidemic spread