Although Central Venous Catheter (CVC) placement is a relatively simple procedure but its insertion and maintenance are associated with significant risks. Malposition (defined as any CVC tip position outside the superior vena cava) may be associated with catheter insertion and may require immediate intervention. It may result in complications like haemothorax, pleural effusions, pneumothorax, sepsis, thrombosis and cardiac tamponade. This case report presents timely detection of the complication after placement of CVC. Everyone should be aware of the complications and monitor consistently appropriate position of catheter tips.
Inconel 718 (IN718) is a nickel based Ni-Cr-Fe super alloy. It has a unique set of properties such as good workability, corrosion resistance, high temperature strength, favorable weldability and excellent manufacturability. Due to its wide range of applications, IN718 is an alloy of great interest for many industries. Meanwhile, additive manufacturing assisted with laser has caught much interest from researchers and practitioners in the past three decades. In this study, IN718 alloy coupons are manufactured by selective laser melting (SLM) technique. The SLMed IN718 alloys are treated by ultrasonic nanocrystal surface modification (UNSM), and the residual stress distributions underneath the surfaces are measured. It is found that residual stress mostly tensile is induced while building the part by the SLM technique. The tensile stresses can be reduced to almost zero value by post heat treatment. Moreover, the heat treatment helps to homogenize the microstructure, and results in the increase in hardness. More importantly, it is observed that UNSM effectively induces compressive residual stresses in the as-built and heat-treated parts. The residual stresses of compressive nature in as built parts has depth of around 530 μm where as in heat treated parts has a depth of around 530μm.
This study investigates the effects of laser shock peening (LSP) on residual stress, near surface modification, and hardness of Inconel 718 (IN718) specimens manufactured by selective laser melting (SLM) technique. Optical microscope and electron backscattered diffraction (EBSD) is used to characterize the microstructures of both heat-treated and as-built specimens. A nanoindentation test is performed to determine the properties such as the hardness of as-built and heat-treated specimens. Afterward, the hardness along the distance from the LSP treated surface is also defined. To investigate the effect of LSP energy on the mechanical properties of specimens, two levels of LSP energy, e.g., low energy LSP (6.37 GW/cm2) and high energy LSP (8.60 GW/cm2), are carried out on selected samples. With the increase in laser energy density, it is found that both compressive residual stress and hardness increase after LSP treatment. The as-built specimens after high energy LSP treatment show the compressive residual stress of −875 MPa, and the surface hardness increases from 468 HV to 853 HV.
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