On the pitting corrosion resistance of nitrogen alloyed cold worked austenitic stainless steels

Pitting corrosion studies were carried out on cold worked (5%, 10%, 15%, 20%, 30% and 40%) nitrogen-bearing (0.05%, 0.1% and 0.22% N) type 316L austenitic stainless steels in neutral chloride medium. Potentiodynamic anodic polarisation study revealed that cold working up to 20% enhanced the pitting resistance, and thereafter a sudden decrease in pitting resistance was noticed at 30% and 40% cold working. Increase in nitrogen content was beneficial up to 20% cold work in improving the pitting corrosion resistance, beyond which it had a detrimental effect at 30% and 40% cold working. The role of nitrogen in influencing the deformation band width and dislocation configuration is explained based on the results of transmission electron microscopy investigations. Scanning electron microscopy observation of the pitted specimens indicated decreasing size and increasing density of pits, along the deformation bands with increasing nitrogen for 40% cold worked specimens. The macrohardness values increased as the cold working increased from 0% to 40%. X-ray diffraction studies revealed the increased peak broadening of austenite peak {0 2 2} with increase in cold working. The relationship between pitting corrosion and deformation structures with respect to nitrogen addition and cold working is discussed.     

Structural integrity assessment of the containment structure of a pressurised heavy water nuclear reactor using impact echo technique

The impact echo technique is based on the use of transient stress waves for non-destructive detection of flaws in concrete structures. Impact-echo testing has been carried out for assessment of the structural integrity of the ring beam of a pressurised heavy water nuclear reactor. In order to develop the test procedure for carrying out impact echo testing, mock up calibration blocks were made. The detectability of the impact echo system has also been established in terms of the depth and the lateral dimension of the detectable flaw for the ring beam under consideration. Based on the optimised test parameters identified with the help of the studies carried out on the mock up blocks, impact echo testing was carried out on the ring beam of the reactor containment structure, for assessing its structural integrity.     

Friction stir scribe welding technique for dissimilar joining of aluminium and galvanised steel

Friction stir scribe technology, a derivative of friction stir welding, was applied for the dissimilar lap welding of an aluminium alloy and galvanised mild steel sheets. During the process, the rotating tool with a cobalt steel scribe first penetrated the top material – aluminium – and then the scribe cuts the bottom material – steel. The steel was displaced into the upper material to produce a characteristic hook feature. Lap welds were shear tested, and their fracture paths were studied. Welding parameters affected the welding features, including hook height, which turned out to be highly related to fracture position. Therefore, in this paper, the relationships among welding parameters, hook height, joint strength and fracture position are presented. In addition, the influence of zinc coating on joint strength was also studied.     

Uranyl ions uptake on poly(AAc/AAm)-cl-N,N-MBAAm hydrogel

In the present article, we report two well-characterized hydrogels for the adsorption of uranyl ions from 5% NaCl solution. The hydrogel was synthesized by free radical initiation from acrylamide and acrylic acid using N,N-methylenebisacrylamide as crosslinker. In order to improve ion uptake performance, the hydrogel was hydrolyzed to partially convert some of the amide groups into carboxylate groups. The uranyl ion adsorption was studied as a function of hydrogel structure, uranyl ions concentration, pH, temperature, and mass of hydrogel. The partially hydrolyzed hydrogel exhibited the maximum uranyl ion uptake of 236.6 mgg⁻¹ in 480 min at 45 °C and at pH 13. Good reproducibility of results was observed and the evidence of sorption at the optimum pH and ion concentration was obtained by comparison of FTIR spectra of the precursor and uranyl ions loaded hydrogels. The performance of both the hydrogels was found to be higher than that of a commercial resin, Amberlite IRC-718. The experimental data shows good match with Langmuir and Freundlich isotherms and pseudo-first order kinetics.     

The effect of modifying an edge-plane pyrolytic graphite electrode with single-wall carbon nanotubes on its use for sensing diclofenac

A simple and highly sensitive sensor based on edge-plane pyrolytic graphite electrode (EPPGE) coated with single-wall carbon nanotubes is proposed for diclofenac determination in nanomolar concentrations. The oxidation of diclofenac occurred in two well-defined peaks having peak potentials ∼439 and ∼854 mV at pH 7.2. The modified electrode showed excellent catalytic activity presenting much higher peak currents than those measured on a bare EPPGE. Under the optimum conditions, the calibration curve was linear in the concentration range 1 × 10⁻⁹-500 × 10⁻⁹ M and 25 × 10⁻⁹-1500 × 10⁻⁹ M for peaks I and II, respectively. The limit of detection for peaks I and II was found as 0.82 × 10⁻⁹ and 22.5 × 10⁻⁹ M, respectively. The developed sensor was applied for the determination of diclofenac in biological and pharmaceutical samples using square-wave voltammetry and the validation of results using high performance liquid chromatography showed excellent agreement.     

Validation of SV2A-Targeted PET Imaging for Noninvasive Assessment of Neuroendocrine Differentiation in Prostate Cancer

Neuroendocrine prostate cancer (NEPC) is an aggressive and lethal variant of prostate cancer (PCa), and it remains a diagnostic challenge. Herein we report our findings of using synaptic vesicle glycoprotein 2 isoform A (SV2A) as a promising marker for positron emission tomography (PET) imaging of neuroendocrine differentiation (NED). The bioinformatic analyses revealed an amplified SV2A gene expression in clinical samples of NEPC versus castration-resistant PCa with adenocarcinoma characteristics (CRPC-Adeno). Importantly, significantly upregulated SV2A protein levels were found in both NEPC cell lines and tumor tissues. PET imaging studies were carried out in NEPC xenograft models with ¹⁸F-SynVesT-1. Although ¹⁸F-SynVesT-1 is not a cancer imaging agent, it showed a significant uptake level in the SV2A⁺ tumor (NCI-H660: 0.70 ± 0.14 %ID/g at 50–60 min p.i.). The SV2A blockade resulted in a significant reduction of tumor uptake (0.25 ± 0.03 %ID/g, p = 0.025), indicating the desired SV2A imaging specificity. Moreover, the comparative PET imaging study showed that the DU145 tumors could be clearly visualized by ¹⁸F-SynVesT-1 but not ⁶⁸Ga-PSMA-11 nor ⁶⁸Ga-DOTATATE, further validating the role of SV2A-targeted imaging for noninvasive assessment of NED in PCa. In conclusion, we demonstrated that SV2A, highly expressed in NEPC, can serve as a promising target for noninvasive imaging evaluation of NED.     

Design of Dual-Gate P-type IMOS Based Industrial Purpose Pressure Sensor

Silicon - In this treatise, we have proposed a Single Material Gate–Dual Gate Impact Ionization Metal Oxide Semiconductor (SMG DG-IMOS) based Pressure Sensor. The pressure sensor has the most...     

Novel Hybrid Silicon SETMOS Design for Power Efficient Room Temperature Operation

Silicon - A novel hybrid silicon Single Electron Transistor Metal Oxide Semiconductor (SETMOS) logic is evaluated for its functionality and usability. Emphasis is given on obtaining functionality...     

Analytical Modelling and Simulation of Si-Ge Hetero-Junction Dual Material Gate Vertical T-Shaped Tunnel FET

Silicon - In this paper, a compact 2D analytical modelling of surface potential and simulation of Si-Ge hetero-junction Dual Material Gate Vertical t-shape T-FET is presented. In the proposed...     

Effect of hook characteristics on the fracture behaviour of dissimilar friction stir welded aluminium alloy and mild steel sheets

ABSTRACT

Under tensile shear loading, fracture modes of dissimilar lap welds produced by friction stir scribe technology were studied. Three fracture modes were observed. For zone A fracture, the initial crack was restrained, and the joint ultimately fractured in the base mild steel. For zone B fracture, the initial crack progressed through the aluminium sheet just above the Al/steel interface. For zone C fracture, the initial crack proceeded along the steel hook to the aluminium sheet surface. Fracture mode and joint strength were greatly influenced by steel hook size, and the steel hook size was affected by welding parameters and tool scribe height. In this study, the experimental joint strength achieved the calculated joint load limit.