Development of Low-Oxide MCrAlY Coatings for Gas Turbine Applications

Advanced high-energy plasma systems are being used to achieve the benefits of the high-velocity oxy-fuel (HVOF) system without losing the inherent advantages of plasma for coating of gas turbine parts. MCrAlY coatings play a very important role in the performance and reliability of gas turbine components. One of the important considerations for next generation of gas turbines, which have more demanding conditions and need to withstand ever increasing operating temperatures, is that they should possess very low oxygen content levels in the coating. Low oxygen content coatings are applied by the expensive low-pressure plasma spray (LPPS)/vacuum plasma spray (VPS) technique for critical components in aero- and land-based gas turbines. This work deals with the development of low-cost LPPS equivalent coatings (having low oxygen content) using the high-energy high-velocity plasma spray (HEHVPS) gun and inert gas shroud. A comparison has also been made with CoNiCrAlY coatings by HVOF.     

Salt-tolerant and thermostable alkaline protease from Bacillus subtilis NCIM no. 64

The proteolytic activity produced by a Bacillus subtilis isolated from a hot spring was investigated. Maximum protease production was obtained after 38 h of fermentation. Effects of various carbon and nitrogen sources indicate the requirement of starch and bacteriological peptone to be the best inducers for maximum protease production. Requirement for phosphorus was very evident, and the protease was secreted over a wide range of pH 5-11. The partially purified enzyme was stable at 60 degrees C for 30 min. Calcium ions were effective in stabilizing the enzyme, especially at higher temperature. The enzyme was extremely salt tolerant and retained 100% activity in 5M NaCl over 96 h. The molecular weight of the purified enzymes as determined by SDS-PAGE was 28,000. The enzyme was completely inactivated by PMSF, but little affected by urea, sodium dodecyl sulfate, and sodium tripoly phosphate.     

Nerve conduction velocity and H-reflex recovery in bipolar illness

Bipolar illness may be characterized by dysregulation and dysfunction of biologically active ions and ion pumps, respectively. In an effort to examine whether purported physiologic abnormalities may have functional counterparts, nerve conduction velocities (NCVs) and H-reflex recovery were examined in 7 acutely manic, 11 euthymic bipolar, 13 remitted schizophrenic, and 6 normal control individuals. All electrophysiologic tests were clinically normal. However, euthymic bipolar patients had significantly slower NCVs than either manic or normal individuals. Percent decrement of H-reflex recovery was nonsignificantly increased in manic versus euthymic bipolar subjects. Data analysis suggests lithium was not responsible for these changes. These data indicate that different mood states in bipolar illness are associated with alterations in electroneurophysiologic function.     

Refurbishment and safety upgradation of research reactor Cirus

Cirus, a 40 MW t, vertical tank type research reactor, having wide range of research facilities, was commissioned in the year 1960. This research reactor, situated at Mumbai, India has been operated and utilized extensively for isotope production, material testing and neutron beam research for nearly four decades. With a view to assess the residual life of the reactor, detailed ageing studies were carried out during the early 1990s. Based on these studies, refurbishment of Cirus for its life extension was taken up. During refurbishment, additional safety features were incorporated in various systems to qualify them for the current safety standards. This paper gives the details of the operating experiences, utilization of the reactor along with methodologies followed for carrying out detailed ageing studies, refurbishment and safety upgradation for its life extension.     

Priority-based joint EDF–RM scheduling algorithm for individual real-time task on distributed systems

The Journal of Supercomputing - Multiple tasks arrive in the distributed systems that can be executed in either parallel or sequential manner. Before the execution, tasks are scheduled prioritywise...     

Consensus-based data replication protocol for distributed cloud

The Journal of Supercomputing - Data availability ensures efficient data accessibility by the readers anytime and from anywhere. It can be addressed by creating multiple copies of each data file...     

Iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film for antibacterial application

Iodine-loaded poly(silicic acid) gellan nanocomposite film was fabricated and evaluated for antibacterial properties. Poly(silicic acid) nanoparticles were synthesized by condensation of silicic acid under alkaline conditions in the presence of polyvinyl pyrrolidone, phosphate ions, and molecular iodine. The nanoparticles were incorporated into gellan dispersion to prepare gellan nanocomposite film using the solvent casting method. The nanocomposite films were characterized by Fourier transformed infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction studies. The results of characterization studies indicated improved thermal stability and an increase in the degree of crystallinity. The scanning electron micrographs and energy dispersive X-ray spectrum confirmed the uniform dispersion of silica and iodine in the nanocomposite films. The analysis of physical and mechanical properties revealed the enhanced tensile strength, moisture resistance, and higher folding endurance of poly(silicic acid) gellan nanocomposite films as compared to gellan film. Further, the iodine-loaded poly(silicic acid) gellan nanocomposite films showed good antibacterial activity against Staphylococcus aureus and Escherichia coli and effective mucoadhesive strength. The results indicate that iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film can be used for potential antibacterial applications in pharmaceuticals.     

An investigation of phase transformation behavior in sputter-deposited PtMn thin films

Sputter-deposited, equiatomic PtMn thin films have application in giant magnetoresistive spin valves, tunneling magnetoresistive spin valves, and magnetic random access memory. However, the as-deposited films are found to be a disordered A1 phase in a paramagnetic state rather than an antiferromagnetic phase with L1₀ structure, which is needed for device operation. Therefore, a postannealing step is required to induce the phase transformation from the asdeposited A1 face-centered-cubic phase to the antiferromagnetic L1₀ phase. The A1 to L1₀ metastable transformation was studied by x-ray diffraction and differential-scanning calorimetry. An exothermic transformation enthalpy of −12.1 kJ/mol of atoms was determined. The transformation kinetics were simulated using the Johnson-Mehl-Avrami analysis.