Stress Corrosion Cracking of Ring Type Joint of Reactor Pipeline of a Hydrocracker Unit

Failure of a ring type joint (RTJ) of reactor pipeline of a hydrocracker unit has been reported. Cracks were noticed on the flange as well as the ring gasket of the RTJ during inspection following a periodic shutdown of the unit. These components of the RTJ were manufactured from stabilized grades of austenitic stainless steel, namely, type 321 and 347, respectively. Study showed that the failure of the RTJ components occurred by transgranular stress corrosion cracking. It was further established that formation of polythionic acid due to presence of H₂S in the process gas and H₂O in the system was responsible for initiation of SCC in RTJ components. Detailed metallurgical investigation was carried out to identify the probable causes that could have been responsible for formation of polythionic acid in the process gas.     

Comments on “VLSI implementation of Reed-Solomon encoder algorithm for communication systems”

This comment points out the four inaccurate equations and incorrect output parity values computed using RS(255, 223) encoder algorithm. The four correct equations and correct output parity values for the given input are provided here.     

Decoupling Capacitor Estimation and Allocation using Optimization Techniques for Power Supply Noise Reduction in System-on-Chip

Journal of Electronic Testing - This article examines the signal integrity problem arising due to resistive drop, inductive noise and electro- migration, causing voltage fluctuations known as...     

Using electrochemical impedance spectroscopy to predict the corrosion resistance of unexposed coated metal panels

The goal of the current work was to determine if electrochemical impedance spectroscopy (EIS) testing of a series of coated but unexposed metal panels could predict the corrosion results of other sections of the same coated panels that were subjected to both continuous and cyclic corrosion testing. Variables included metal, pretreatment, primer, and topcoat. EIS results were shown to be strongly dependent upon the time-of-residence in the electrochemical cell prior to commencement of testing, and to the choice of electrolyte used in the cell. Good correlations between EIS and corrosion testing were seen for topcoat effects, but not for pretreatment effects. EIS results appear to relate mostly to barrier properties rather than electrochemical properties of coatings. It is suggested that the variation seen in EIS solution resistance values (R_s) can be utilized to quantify total system error. Total error was estimated by three techniques: total R_s variation, panel replicate variation, and EIS reading replication. The three approaches yielded similar results: total error for equivalent circuit components expressed in log₁₀ form was on the order of 50%, expressed as percent standard deviation.     

Failure analysis of oxygen hose of the lance equipment in LD shop of Tata steel

The hose of the oxygen lancing equipment in LD shop # 2 has failed at the weld–bellows interface by reverse bending fatigue. The bending stresses were resulted due to inclined fitting of the hose at the fixed flange end. No metallurgical abnormalities or weld defects or mechanical damages were responsible for the fatigue crack initiation. It is recommended that if inclined fitment of the hose is not a process requirement, the original design be restored to realize the expected life of the component. On the other hand, if inclined fitment cannot be avoided, additional support may be provided for the hose at the fixed flange end to avoid reverse bending at the weld–bellows interface. A detailed analysis of the failure is presented in this report.     

New mesoporous titanium–phosphorus mixed oxides having bifunctional catalytic activity

New mesoporous titanium–phosphorus mixed oxides templated by non-ionic triblock copolymer Pluronic F127 under evaporation induced self-assembly (EISA) method and using unconventional phosphorus source trimethylphosphite have been reported. Powder XRD, TEM and N₂ sorption studies are employed to characterize the mesophases. TPD-NH₃ experiments suggested an increase in surface acidity with the increase in the molar ratio of Ti/P in these mesoporous mixed oxides from 1 to 2. Interestingly these mesoporous materials showed excellent bifunctional catalytic activity in acid catalyzed Friedel–Crafts benzylation of bulky aromatics and partial oxidation of styrene to benzaldehyde with dilute H₂O₂ oxidant under mild liquid phase conditions.     

Attacks and Remedies in Collaborative Recommendation

Collaborative-filtering recommender systems are an electronic extension of everyday social recommendation behavior: people share opinions and decide whether or not to act on the basis of what they hear. Collaborative filtering lets you scale such interactions to groups of thousands or even millions. Publicly accessible user-adaptive systems such as collaborative recommender systems introduce security issues that must be solved if users are to perceive these systems as objective, unbiased, and accurate.     

Validation of an improved dislocation density based flow stress model for Al-alloys

A microstructure and flow stress model for cell forming metals, 3IVM (3 Internal Variables Model), was developed [1], in which the work hardening and softening effects due to interaction of dislocation densities are taken into account. This model had been applied in through process modelling of sheet production. In the present paper, improvements of 3IVM are introduced. In the new model (3IVM+) the softening effect of recovery by cross slip and by additional dislocation reactions are considered in addition to that of climb. Moreover an improved kinetic equation of state is utilized. For validation, compression tests on a commercial Al-alloy were carried out and the flow curves were determined. The comparison between model predictions and experimental results shows that 3IVM+ can replicate the flow curves much better than the previous model, in particular at low temperatures and in wide temperature range. Since the concept of the model is unchanged, its applicability for through process modelling is not compromised.