Archives-November 2021

Management is a science that focuses on the management of companies and organizations as well as various institutions. That is its main focus. Peter Drucker defined management as "the process of coordinating the activities of a group of employees [is] carried out by an individual or a group of people to achieve certain results that cannot be achieved by individual practice." material, information). In our contribution, we want to focus on current management and its important role in helping companies adapt to the changing market environment.

The assessment of heavy metals (Hg, Cu, Pb and Cd) by means of a Peroxidase - based assay is here presented. The method is based the inhibition of peroxidase activity by heavy metals. Measurements were made spectrophotometrically via the catalytic oxidation of guaiacol in the presence of H2O2. Preliminary characterization and optimization of the assay system revealed enzyme activity of 130 U/ml, Vmax of 0.178mM/min and Km of 0.184mM. Optimal reaction time was found to be 7 minutes; optimal pH was 6 and temperature was 40°C. Inhibition-based estimation of heavy metal ions was evaluated via calibration curves of metal concentration against %inhibition of peroxidase activity. The assay revealed detection limits between 0.006 – 0.045mg/L for the metals and repeatability in the range of 2.3 – 5.4% RSD. Application of the method to water analysis revealed percentage recoveries between 76.0 – 124.0%. Overall, the method showed good potential for further use in the biomonitoring of heavy metal pollutants

Radon is one of the most important radioactive elements which are released by natural decay of available uranium and radium in the ground. The presence of the gas is common in various drinking water sources. As a way of prevention, we have measured the activities of radon for sixty-four (64) drinking water samples collected from boreholes and hand-dug wells. This study was conducted during the dry season (December-January) of 2016. The samples were collected from sixty-four (64) water sources (boreholes and hand-dug wells). The concentration of radon was evaluated using solid state nuclear track detector LR-115 type II, with an active layer of 12 ?m on a 100 ?m clear base. The minimum radon concentration in the water sources was 30.17 Bq/m3 (hand-dug well) and the maximum amount was calculated as 115.33 Bq/m3(borehole). Based on the results, radon concentration of the drinking water sources was below the permitted levels of EPA and WHO guidelines. These activities do not present any health risk to the community.

Austenitic stainless steels (ASS) represent the largest group of stainless steels and have maximum usage in industry. AISI 316L austenitic stainless steel is widely used as a structural material in chemical, petrochemical, power engineering and aviation industries owing to its good combination of mechanical properties, corrosion resistance and weldability. In view of industrial importance of this stainless steel, the proposed work would comprise of fabricating welded joints on 10mm thick AISI 316L using two different groove designs viz. Single-V groove and Narrow gap and submerged arc welding process. In view of the service applications that this alloy is subjected to, the joints will be subjected to thermal aging to high temperature of 750°C for 24 hours duration. The joints were thermally aged to study effects of precipitation at high temperature (750°C/24 hrs.) aging condition on different welds. For analyzing different aspects of these welds different specimens were extracted from the welded plates and were further subjected to metallurgical, corrosion and fatigue testing.The metallurgical testing were carried out via optical microscopy, ferrite content evaluation and microhardness measurements. Further, corrosion performance was evaluated using potentiodynamic scan for determining the pitting corrosion resistance of AISI 316L welds with different joint designs. The fatigue crack propagation behavior of different welds was determined through fatigue testing of above-mentioned welds. The results of corrosion and fatigue crack growth performance of AISI 316L welds with different joint designs and thermal aging were correlated with metallurgical observations. Mixed morphology of lacy and skeletal ferrite along with lower ferrite content and higher microhardness were observed for narrow gap butt weld as compared to single V-weld. Further, pitting corrosion resistance was also improved for joints prepared with narrow gap butt weld. The FCGR performance of narrow gap butt weld was also improved as compared to single V butt weld. Aging at high temperature reduced the pitting corrosion performance but increased the fatigue performance owing to accelerated precipitation in AISI 316L welds with different joint designs.

Table of contents for the month of November 2021