Hyperbranched poly(cyanurateamine): A new corrosion inhibitor for mild steel in hydrochloric acid medium

Hyperbranched poly(cyanurateamine) (POCYAM) was tested as a novel corrosion inhibitor for mild steel in 0.5–3 M HCl using chemical and electrochemical techniques at 25–70 °C. The results show that this compound has good corrosion inhibiting properties for mild steel in HCl at very low concentrations. Corrosion inhibition efficiency rises with POCYAM concentration. The adsorption of the POCYAM onto the mild steel surface obeys Langmuir adsorption isotherm model. The inhibition mechanism was further corroborated by the values of thermodynamic parameters obtained from the experimental data.     

Effect of amphiphilic compatibilizers on the filler dispersion and properties of polyethylene—thermally reduced graphene nanocomposites

Compatibilizers of different chemical structures and specifications were used to enhance the filler exfoliation in nanocomposites of polyethylene and thermally reduced graphene prepared by melt mixing route. The mechanical performance of the compatibilized nanocomposites was observed to be better than PE/G nanocomposites due to enhanced extent of filler exfoliation and distribution. Highest increase of 45% in tensile modulus and 13% in peak stress was observed in the composites. Overall, from the mechanical, rheological, thermal, and calorimetric properties, the compatibilizers with best performance were ethylene acrylic acid (EAA) copolymer and chlorinated polyethylene (CPE25). Furthermore, the extent of filler exfoliation was observed to increase with increasing EAA content thus confirming positive interactions between EAA and thermally reduced graphene, though no specific chemical interactions could be detected. The composite properties were observed to reach maximum around 7.5 wt % EAA content, followed by reduced performance due to extensive matrix plasticization. The observed behaviors were a result of interplay of opposing factors like filler exfoliation due to compatibilizer addition and matrix plasticization due to its lower molecular weight, thus the observed optimum comaptibilizer amount was specific to the compatibilizer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42484.     

Enhancement of room temperature ferromagnetism in Cd1−xNixSe nanoparticles

Cd_1?xNi_xSe (x = 0.0, 0.02, 0.05 and 0.1) nanoparticles have been synthesized by chemical route. X-ray diffraction analysis shows crystalline nature of synthesized nanoparticles possessing wurtzite phase having hexagonal structure. Transmission electron microscopy depicts spherical morphology and uniform particle size distribution of pure and Ni-doped CdSe nanoparticles. The blue-shift in band gap has been observed with Ni-doping concentration. Photoluminescence study shows the presence of intrinsic defects (V_Cd–V_Se) in the synthesized nanoparticles. Electron spin resonance (ESR) analysis reveals the long range ferromagnetic ordering in pure and doped nanoparticles. ESR study also indicates that Ni ions exist in +2 oxidation state in host nanoparticles. The magnetic hysteresis (M-H) loops display ferromagnetism at room temperature in pure and Ni-doped CdSe nanoparticles. The increase of ferromagnetic behavior has been observed with Ni-doping concentration. M-H analyses indicate that defects and carrier mediated exchange interactions are responsible for ferromagnetic ordering, in the present study.     

Separation of nickel from copper in ammoniacal/ammonium carbonate solution using ACORGA M5640 by selective stripping

Separation of nickel from copper in ammoniacal/ammonium carbonate solution using ACORGA M5640 by selective stripping was carried out. The influence of equilibration time, equilibrium pH and extractant concentration on the extraction of both the metals was studied. It was found that the copper extraction equilibrium was reached in a shorter time than the nickel extraction equilibrium. Nickel extraction decreases above an equilibrium pH of 9.0, while the extraction of copper remains unaffected by the changes in the equilibrium pH range of 7–10. Co-extraction, ammonia scrubbing and the selective stripping of copper and nickel were performed for a solution containing 3 g/l each of copper and nickel and 60 g/l ammonium carbonate. The extraction and the percentage stripping of copper and nickel were almost quantitative.     

Combined Effect of Turbulence,Load Orientation and Rotor Flexibility on the Performance of Three-Lobe Bearings

A three-lobe journal bearing is analytically investigated to determine its dynamic performance when three main parameters, i.e. turbulence, load orientation, and rotor flexibility are varied. Reynolds numbers up to 12000, rotor dimensionless flexibilities up to 4, and load orientations up to 30 degrees on either side of the vertical load line are considered. Thus, almost all cases of practical interest are studied. The stability of a three-lobe bearing improves due to turbulence at high Sommerfeld numbers (more than 0.6) for a rigid rotor, while it is virtually the same for flexible rotors. Conversely, the load orientation has a pronounced effect on stability for both rigid and flexible rotors.     

A High-Density 45 nm SRAM Using Small-Signal Non-Strobed Regenerative Sensing

High-density SRAMs utilize aggressively small bit-cells, which are subject to extreme variability, degrading their read SNM and read-current. Additionally, array performance is also limited by sense-amplifier offset and strobe-timing uncertainty. This paper, presents a sense-amplifier that targets all of these performance degradations: specifically, simple offset compensation reduces sensitivity to variation while imposing minimal loading on high-speed nodes; stable internal voltage references serve as an internal means to self-trigger regeneration to avoid tracking mismatch in an external strobe-path; precise small-signal detection withstands small read-currents so that other bit-cell parameters can be optimized; and single-ended sensing provides compatibility to asymmetric bit-cells, which can have improved operating margins. The design is integrated with a 64-kb high-density array composed of 0.25 mum² 6T bit-cells. A prototype, in low-power 45 nm CMOS, compares its performance with a conventional sense-amplifier, demonstrating an improvement of 4X in access-time sigma and 34% in overall worst case access time.     

Comparison of deformation induced precipitation behaviour in Alloy 718 under two microstructural conditions

Alloy 718 samples under two initial microstructural conditions, viz., solution annealed to form only γ phase (ST) and aged to precipitate only δ particles (DELTA), were deformed in tension till fracture in the temperatures range from 200°C–700°C. From the comparison of the evolved microstructure of deformed and undeformed specimens that have been subjected to similar thermal history, deformation induced precipitation could be identified. Deformation in the range of 550°C to 650°C promoted the precipitation of γ′ and γ″ phases in both structures. In case of DELTA alloy, the γ′ precipitation was found to precede the γ′ phase precipitation while no such preference for precipitation could be identified in ST specimens. This difference in the precipitation behaviour and the sequence of precipitation has been explained on the basis of the relative concentration of solutes in the matrix of the starting microstructures of ST and DELTA specimens.