The comparison of performance of electrolytic cu and cube tool electrodes in electric discharge machining of ti6al4v alloy [Ti6al4v alaşımının elektro erozyon ile işlemesinde elektrolitik cu ve cube takım elektrotlarının performansının karşılaştırılması]

The most crucial cost element of Electric Discharge Machining (EDM) is the production of tool electrode (shortly electrode). Copper, its alloys, and graphite are the most commonly used electrode materials. Selecting the proper electrode material with low production and material cost, high workpiece material removal rate (MRR) and low tool electrode wear rate (TWR) is key to reducing machining costs with EDM. In this study, the EDM performance of CuBe tool electrodes in the machining of Ti6Al4V alloy was experimentally investigated in comparison to electrolytic Cu (E-Cu) electrodes for different pulse time (ts) and discharge current (I) settings. An increase in MRR and a decrease in TWR and relative wear (RW=TWR/MRR) were observed in machining with CuBe electrodes. However, the high raw material cost of CuBe alloy is an essential drawback in widely using these electrodes in industrial applications. A new performance index formulation is introduced for EDM applications that factor in the production cost of the electrode and its life (i.e., RW). According to our results, the CuBe could be used advantageously as the electrode material at medium current settings. However, at low and high current settings, the low raw material cost of E-Cu makes it more favorable. © 2021, TUBITAK. All rights reserved

Heavy Metals in the Blue Crab (Callinectes sapidus) in Mersin Bay, Turkey

PubMedID: 28409194The concentrations of four metals (copper, cadmium, zinc and lead) were quantified in blue crabs (Callinectes sapidus) tissues collected in January, April, June and September at two stations in Mersin Bay, northeastern Mediterranean Sea, using ICP-MS. The metal concentrations in crabs from the two stations differed significantly. The hepatopancreas was the major organ accumulating metals, followed by gill and muscle tissues. Except for lead, the highest concentrations of metals were measured in the hepatopancreas. The hepatopancreas had higher concentrations of all heavy metals (Cu 321.1 ± 4.30; Zn 182.2 ± 3.40; Cd 48.2 ± 2.00) compared to gill (Cu 90.2 ± 1.35; Zn 104.3 ± 2.30; Cd 22.3 ± 3.40) and muscle (Cu 19.1 ± 1.10; Zn 55.1 ± 3.25; Cd 2.5 ± 0.20). Among the metals analyzed, Cu, Zn and Pb were the most abundant in the different tissues while Cd was the least abundant in C. sapidus. Seasonality in the levels of the four metals was determined.The highest concentrations of all metals were observed in the June (Zn 55.1 ± 3.25; Cu 19.1 ± 1.10; Cd 2.5 ± 0.20; Pb 5.1 ± 0.18) compared to all other months (Zn 34.1 ± 3.23; Cu 11.1 ± 1.15; Cd 0.9 ± 0.20; Pb 3.1 ± 0.21). © 2017, Springer Science+Business Media New York