Integration of functional reliability analysis with hardware reliability: An application to safety grade decay heat removal system of Indian 500 MWe PFBR

A passive system can fail either due to classical mechanical failure of components, referred to as hardware failure, or due to the failure of physical phenomena to fulfill the intended function, referred to as functional failure. In this paper a methodology is discussed for the integration of these two kinds of unreliability and applied to evaluate the integrated failure probability of the passive decay heat removal system of Indian 500 MWe prototype fast breeder reactor (PFBR). The probability of occurrence of various system hardware configurations is evaluated using the fault tree method and functional failure probabilities on the corresponding configurations are determined based on the overall approach reported in the reliability methods for passive system (RMPS) project. The variation of functional reliability with time, which is coupled to the probability of occurrence of various hardware system configurations is studied and incorporated in the integrated reliability analysis. It is observed that this consideration of the dependence of functional reliability on time will give significant advantages on system reliability. The integrated reliability analysis is also explained using an event tree. The impact of the provision for forced circulation in the primary circuit on functional reliability is also studied with this procedure and it is found that the forced circulation capability helps to bring down the total decay heat removal failure probability by lowering the peak temperatures after the reactor shut down.     

Online APAN IPv6 Network Monitoring

APAN [4] has native IPv6 network across all major APAN exchange points. It is important to validate the performance of the links in the network to ensure the link stability. This paper discusses the technique and mechanism that are used to perform online monitoring of the APAN IPv6 network status. Pchar tool is used to check the performance of the network. Metrics such as bandwidth, hop count and round trip time between nodes in each country's have been adopted for these monitoring activity.     

Growth and Optical Studies of a Novel Organometallic Complex NLO Crystal: Tetrathiourea Cadmium(II) Tetrathiocyanato Zinc(II)

Tetrathiourea cadmium(II) tetrathiocyanato Zinc(II) (TCTZ) single crystals were grown in acetone-water mixture solvent using slow solvent evaporation technique and their optical property was studied for the first time. Both thiourea and thiocyanate ligands were combined with the transition metal ions Cd²⁺ and Zn²⁺. The nonlinear optical (NLO) efficiency of TCTZ crystal was tested and measured using Kurtz and Perry technique. The dielectric behavior of the sample was also studied.     

Electrochemical and oxygen reduction behaviour of solid silver-bismuth/antimony electrodes in KOH solutions

Oxygen reduction behaviour at silver-low bismuth/antimony electrodes was investigated by electrochemical methods in KOH solutions. The electrochemical redox characteristics such as peak multiplicity, peak currents and peak potentials on these electrodes under both potentiostatic steady state and cyclic voltammetric conditions were obtained. The anomalies associated with the redox peak potential values both in the anodic and cathodic branches of the cyclic voltammograms were attributed to the distinct electrochemical behaviour of bismuth/antimony on the electrode surface along with silver. The behaviour of these electrodes for the electrocatalytic cathodic reduction of oxygen was also investigated both by potentiostatic steady state and cyclic voltammetric techniques under rotating conditions. The kinetic parameters corresponding to the electrochemical reduction of oxygen on these electrodes were obtained. These electrodes were ranked with respect to their electrocatalytic activity both for the oxygen reduction and evolution reactions.     

Nephroprotective role of nanoencapsulated Tinospora cordifolia (Willd.) using polylactic acid nanoparticles in streptozotocin‐induced diabetic nephropathy rats

Currently, the field of nanomedicine, which uses active compounds from medicinal plants, has emerged as a therapy for diabetic nephropathy. From this study, the renoprotective effect of TC‐loaded PLA Nanoparticles (TC‐PLA NPs) on streptozotocin (STZ)‐induced diabetic nephropathy rats was investigated. The results showed that the nephroprotective effect of TC‐PLA NPs reduces the blood glucose level, regulates the renal parameters, decreases the cytokine levels and reduces the mRNA expressions level of different genes related to diabetic nephropathy.     

Studies on antimicrobial and wound healing applications of gauze coated with CHX–Ag hybrid NPs

In this study, chlorhexidine (CHX)–silver (Ag) hybrid nanoparticles (NPs) coated gauze was developed, and their bactericidal effect and in vivo wound healing capacities were tested. A new method was developed to synthesise the NPs, wherein Ag nitrate mixed with sodium (Na) metaphosphate and reduced using Na borohydride. Finally, CHX digluconate was added to form the hybrid NPs. To study the antibacterial efficacy of particles, the minimal inhibition concentration and biofilm degradation capacity against Gram‐positive and Gram‐negative bacteria was studied using Escherichia coli and Staphylococcus aureus. The results indicated that the NP inhibited biofilm formation and was bactericidal as well. The gauze was doped with NPs, and its wound healing property was evaluated using mice model. Results indicated that the wound healing process was fastened by using the NPs gauze doped with NPs without the administration of antibiotics.Inspec keywords: nanomedicine, nanoparticles, wounds, silver, cellular biophysics, biomedical materials, nanofabrication, microorganisms, antibacterial activityOther keywords: NPs gauze, antimicrobial wound healing applications, hybrid NPs, chlorhexidine–silver hybrid nanoparticles, CHX, coated gauze, bactericidal effect, minimal inhibition concentration, biofilm degradation capacity, Gram‐negative bacteria, wound healing property, wound healing process, in vivo wound healing capacities, Staphylococcus aureus, Escherichia coli, antibiotics administration, Na borohydride, Ag nitrate mixing, sodium metaphosphate, CHX digluconate, NP inhibited biofilm formation, Ag     

Mosquito-larvicidal efficacy of gold nanoparticles synthesized from the seaweed,Turbinaria ornata (Turner) J.Agardh 1848

Malaria is considered a dreadful mosquito-borne infectious disease of human beings caused and spread by biting of the female mosquito Anopheles stephensi infected with a parasitic protozoan Plasmodium falciparum. Continuous application of chemicals/synthetic insecticides for vector control causes various problems such as resistant mechanism of mosquito, toxicity to nontarget aquatic organisms and disturbance to the microbial community of the soil. Currently, green synthesized nanoparticles are being employed in various biological processes including insect and pest control. The present investigation focused on the mosquito-larvicidal property of Turbinaria ornata-mediated gold nanoparticles (To-AuNPs) and its boiled aqueous extract (To-AE) against the malarial vector A. stephensi. The recorded lethal concentration (LC₅₀ and LC₉₀) values (µg/ml) of To-AE and To-AuNPs against fourth instar larvae of A. stephensi were 37.77 and 159.55 and 12.79 and 78.70, respectively. The To-AuNPs were characterized through UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDX), zeta potential and dynamic light scattering (DLS) method. The presently synthesized gold nanoparticles through the single-step, eco-friendly method is a potentially effective mosquitocidal agent.     

Synthesis of CeO2 nanorods with improved photocatalytic activity: comparison between precipitation and hydrothermal process

The main purpose of this article is to examine the surface free cerium oxide (CeO₂) nanostructures prepared by different methods. CeO₂ nanoparticles and nanorods were prepared by two different methods including precipitation and hydrothermal process. In precipitation process the nanoparticles were prepared at room temperature, while in hydrothermal process nanorods were prepared at high temperature. X-ray and electron diffraction analysis show the presence of CeO₂. X-ray photoelectron spectroscopy (XPS) confirms the presence of CeO₂ in both nanostructures. From BET, the specific surface area of nanorods (110 m²g^?1) is found to be higher than nanoparticles (52 m²g^?1). Also, the effect of morphology on their photodegradation of azo dye acid orange 7 (AO7) under UV–Visible light has been successfully investigated. The results show that the CeO₂ nanorods synthesized by hydrothermal method have high surface area and exhibit improved performance in the photocatalytic activity.     

Engineering and environmental evaluation of spent coffee grounds stabilized with industrial by-products as a road subgrade material

Current construction technology increasingly seeks the sustainable usage of waste by-products as a resource material. This paper evaluates the viability of utilizing spent coffee grounds (CG), a highly organic beverage waste, to be stabilized as a road subgrade material. The additives used in this research incorporates industrial by-products such as fly ash (FA), ground granulated blast-furnace slag (S) as well as traditional binders such as portland cement (PC) and hydrated lime (L). CG collected from a coffee roaster were mixed with controlled additive content ratios by mass to assess the effects of these common engineering stabilizers towards the load-bearing capacity of CG. The additive contents of FA and S were 10, 20, 30, 40, and 50 % whereas the PC and L additive contents were 3 and 5 % by dry unit weight. Modified proctor compaction tests, 7-days unconfined compressive strength (UCS) tests, and California bearing ratio (CBR) tests were carried out to determine the optimum moisture content and bearing strength of the different mixes produced. It found that as the proportion of additives in the specimen increased, the optimum moisture content of the additive-stabilized CG specimens subsequently decreased. Regardless of the type of stabilizers used, the UCS strength increases were found to be nominal. FA and S mixes above the 20 % additive contents satisfied the requirements for subgrade materials; however, the low PC and L contents were insufficient to meet subgrade requirements. The research findings indicate that instead of being disposed of into landfills, stabilized CG has the potential to be used as a subgrade material. Such a sustainability driven approach for reuse of CG will have the potential to divert CG from landfills and at the same time utilize CG as a viable construction material.