Effect of temperature on the KIscc of steam turbine disc material

A fracture mechanics approach has been used to evaluate the critical stress intensity factor in the corrosive environment (K_Iscc) of a 1.5 Ni? Cr? Mo steel in the temperature range of 50 to 100° C. The K_Iscc value has been found to decrease with increasing temperature of the corrodent. The microscopic and macroscopic features of crack propagation under stress corrosion conditions have been discussed.     

Influence of Saturation Temperature on Pressure Drop during Condensation of R-134a inside a Dimpled Tube: A Numerical Study

Theoretical Foundations of Chemical Engineering - In this study, the numerical simulations for multiphase fluid flow inside a smooth and dimpled tube were investigated at low mass velocities during...     

Spatial Variation of Thermokinetics and Associated Microstructural Evolution in Laser Surface Engineered IN718: Precursor to Additive Manufacturing

Metallurgical and Materials Transactions A - The spatial variation of thermokinetic parameters has a significant influence on solidification and microstructural aspects such as grain orientation,...     

The influence of grain size on the erosion rate of metals

The objective of this work was to understand the influence of grain size on solid impingement erosion behavior characterized by deformation at high strain rates and large strains. Experiments were carried out at a velocity of 40 m/s, impact angle of 90 deg with 300 to 450 μm steel shot as erodent on iron, copper, and titanium with varying grain sizes. The results indicate that the erosion rate is independent of grain size in iron and copper while it is apparently grain size dependent in titanium. The results are rationalized in terms of the negligible contribution of the Hall-Petch component to the flow stress at large strains in the case of copper and iron. The decreasing erosion rate in titanium with increasing grain size was due to the increased interstitial content picked up during thermal treatment and consequent increase in strain hardening and strain rate hardening and not due to increased grain sizeper se. Adiabatic shear bands were observed in coarse-grained iron under actual erosion conditions.     

Optimization of cold and warm workability in 304 stainless steel using instability maps

The deformation characteristics of stainless steel type AISI 304 under compression in the temperature range 20 °C to 600 °C and strain-rate range 0.001 to 100 s^-1 have been studied with a view to characterizing the flow instabilities occurring in the microstructure. At strain rates less than 5 s^-1, 304 stainless steel exhibits flow localization, whereas dynamic strain aging occurs at intermediate temperatures and below 0.5 s^-1. At room temperatures and strain rates less than 10 s^-1, martensite formation is observed. To avoid the preceding microstructural instabilities, cold and warm working should be carried out at strain rates greater than 5 s^-1. The continuum criterion, developed on the basis of the principles of maximum rate of entropy production and separability of the dissipation function, predicts accurately all the preceding instability features. S. VENUGOPAL, Scientific Officer, on leave from the Materials Development Division, Indira Gandhi Centre for Atomic Research     

BW 1023U90: a new GRP receptor antagonist for small-cell lung cancer cells

Gastrin-releasing peptide (GRP) receptor antagonists were synthesized and their ability to interact with small-cell lung cancer (SCLC) cells determined. [125I] BW1023U90, bound with high affinity (Kd = 2 nM) to a single class of sites (Bmax = 55 fmol/mg protein) using SCLC cell line NCI-H345. [125I] BW1023U90 binding was time dependent and reversible even at 37 degrees C as the ligand was minimally internalized. Specific [125I] BW1023U90 binding was inhibited with high affinity by GRP as well as bombesin (BB) but not neuromedin B (NMB). BW1023U90 inhibited the ability of BB to elevate cytosolic Ca2+ and increase the growth of SCLC cells. A BW1023U90 analogue, BW2258U89 (10 micrograms/day, SC) slowed SCLC xenograft format on in nude mice and [125I] BW 1023U90 localized to SCLC tumors 1 h after injection into nude mice. BW2258U89 (4% by weight) was placed in microspheres and slowly released over a 3-week period in nude mice bearing SCLC xenografts. The microspheres containing BW2258U89 strongly inhibited SCLC growth in vivo. A radioimmunoassay was developed for the GRP receptor antagonists and the rabbit antiserum cross-reacted totally with BW2258U89 or BW1023U90. BW2258U89 immunoreactivity (5 nM) was detected in the plasma of nude mice containing the microspheres after 1 week. These data suggest that GRP receptor antagonists bind to receptors on SCLC tumors.     

Fundamental studies on a new series of SPSEBS‐PVA‐QPSEBS bipolar membrane: Membrane preparation and characterization

A sulfonated polystyrene ethylene butylene polystyrene (SPSEBS)‐poly(vinyl alcohol) (PVA)‐Quaternized polystyrene ethylene butylene polystyrene (QPSEBS) bipolar membrane (BPM) was prepared by lamination method using PSEBS as the starting material, the functionalization of which was modified by sulfonation and amination while PVA was used as the intermediate layer to enhance the water splitting efficiency. The cross section view of SPSEBS‐PVA‐QPSEBS BPM was studied by SEM. Fourier transform infra‐red spectroscopy (FTIR) studies indicated that the prepared BPM contained –SO, –NR, and –C‐N functional groups. The thermal stability of the prepared BPM was studied by thermogravimetric analysis (TGA). Some of the BPM characteristics results showed that the co‐ion fluxes was greater for t(0.065) when compared with t(0.051) along with a water splitting capacity value of 0.88 for SPSEBS‐PVA‐QPSEBS BPM. The water dissociation flux was 2.8 × 10^?5 mol/m²/s and 2.2 × 10^?5 mol/m²/s for the acid (H⁺) and base (OH^?), respectively. The other essential current‐voltage characteristics and permeate flux across the membrane were also evaluated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci 2013