Sensitization of Gold Dust in 430 Grade Stainless Steel

\u27Gold dusting\u27 is a surface defect that is sometimes observed on cold-rolled AISI type 430 stainless steel. Gold dusting is characterized by a sparkling appearance, which results from small flakes of metal on the cold rolled surface, the flakes are mostly elongated in the rolling direction. The processing steps include continuous casting, hot rolling, continuous annealing, and pickling. One possibility is that the flakes of metal are grains that had been undercut by intergranular corrosion such intergranular corrosion may occur during pickling after the annealing step (which itself follows hot rolling). If intergranular corrosion does occur during this pickling step, the intergranular cavities would be elongated by subsequent cold rolling; this can account for the observed morphology of gold dusting. If the steel has been sensitized, intergranular corrosion may occur during pickling. Pickling is commonly carried out by electrolytic descaling in a neutral sodium sulphate solution followed by immersion in a nitric acid/hydrofluoric acid bath. The sensitized type 430 stainless steel does, indeed, suffer intergranular corrosion in a nitric acid/hydrofluoric acid bath, while it is largely unaffected during electrolytic pickling. Hence, sensitization is a possible cause of gold dusting

OPTIMIZATION STUDY ON EXTRACTION & PURIFICATION OF PHYCOERYTHRIN FROM RED ALGAE KAPPAPHYCUS ALVAREZII

Objective: The current study focuses on R-Phycoerythrin pigment production from Seaweed using different chemical and physical conditions. Methods: In the present study Seaweed was collected from Rameshwaram and identified by CS-MCRI Institute, Mandapam. The collected seaweed was then washed using distilled water for further processing. Using a sterile knife the seaweed was cut into small pieces. The chopped seaweeds were then weighed and subjected to different optimization procedures for pigment production. These equally weighed seaweeds were treated with three varying Buffers at different pH, the buffer showing better O.D value was subjected to different Cell disruption techniques and finally freeze thawed at different temperature stress.Results: The seaweeds were subjected to different chemical and physical stress conditions for R-phycoerythrin production. On optimizing the different buffer solutions for pigment production Sodium phosphate buffer showed maximum O.D of 0.215 when compared to other buffers whereas on providing different pH conditions the O.D value obtained was high at pH 7.2. Different cell disruption techniques were followed for pigment production using the sodium phosphate buffer at pH 7.2 and freeze thaw method was found suitable for the highest pigment production with O.D value of 0.441. Hence after optimization of different extraction procedures, cell disruption followed by freeze & thaw method (−20°C and 25°C) showed maximum R-phycoerythrin content. Conclusion: From the findings, it was also observed that the primary metabolites produced by these organisms may serve as potential bioactive compounds of interest in the Food industries as natural colourant and in cosmetic industries.Keywords: Seaweeds, Extraction, Phycoerythrin, Optimization, Cell disruption, Sonication

A personal-computer-based imaging Stokes polarimeter for solar observations

For measurements of vector magnetic field over solar active regions, a Stokes polarimeter for studying the polarisation profiles on selected spectral lines is described. This paper gives details of the relevant CCD imaging system and the personal computer (PC)-based acquisition, together with the image analysis techniques necessary for the task. Field trials and tests of the system are also described

Leveraging Static Analysis Tools for Improving Usability of Memory Error Sanitization Compilers

Memory errors such as buffer overruns are notorious security vulnerabilities. There has been considerable interest in having a compiler to ensure the safety of compiled code either through static verification or through instrumented runtime checks. While certifying compilation has shown much promise, it has not been practical, leaving code instrumentation as the next best strategy for compilation. We term such compilers Memory Error Sanitization Compilers (MESCs). MESCs are available as part of GCC, LLVM and MSVC suites. Due to practical limitations, MESCs typically apply instrumentation indiscriminately to every memory access, and are consequently prohibitively expensive and practical to only small code bases. This work proposes a methodology that applies state-of-the-art static analysis techniques to eliminate unnecessary runtime checks, resulting in more efficient and scalable defenses. The methodology was implemented on LLVM\u27s Safecode, Integer Overflow, and Address Sanitizer passes, using static analysis of Frama-C and Codesurfer. The benchmarks demonstrate an improvement in runtime performance that makes incorporation of runtime checks a viable option for defenses