A mathematical model to characterize effect of silica content in the boiler fly ash on erosion behaviour of boiler grade steel

Fly ash particles entrained in the flue gas of coal-fired boilers can cause serious erosion on the critical components along the flow path. Such erosion can significantly jeopardise operational life of the boiler. A first principle based theoretical model has been developed embodying the mechanisms of erosion involving cuttingwear, plastic deformationwear and effect of temperature on erosion behaviour, to predict erosion rates of pertinent boiler grade steels. Various grades of steels commonly used in the fabrication of boiler components and published data pertaining to boiler fly ash has been used in modelling the phenomena. The model also provides a quantitative predictive framework to study the effect of percentage of silica content in the ash particles on the erosion potential. The erosion sensitivity of particle impact velocity, angle of impingement and variation of surface temperature of the substrate (steel) have also been studied as a function of silica content in the ash. The model has been implemented in a computer code to predict the erosion rates at room and elevated temperature for various grades of steels under different particle impact conditions. The model predictions have been found to be in good agreement with the published data. This investigation illustrated that any minor increase in silica level in the ash can considerably aggravate the erosion rates, signifying the fact that silica content in the ash plays a critical role in characterising erosion potential of fly ash

Mathematical modelling of ductile erosion behaviour of impacted fly ash particles on steel components of a coal fired boiler

In coal-fired power stations about 20% of tie ash produced in the boilers is deposited on the boiler walls, economisers, air-heaters and super-heater tubes. An abin-itio, first principle based mathematical model embodying the mechanisms of erosion involving cutting, wear, plastic deformation wear and effect of temperature on erosion behaviour has been developed to predict erosion rates on the coal fired boiler components such as boiler tubes, economiser and air-preheater assemblies at room and elevated temperature

Mathematical Modelling of ductile erosion behaviour of impacted fly ash particles on steel components of coal fired boiler

In coal-fired power stations about 20% of the ash prod-uced in the boilers is deposited on the boiler walls, economisers, air-heaters and super-heater tubes. An abinitio, first principle based mathematical model emb-odying the mechanisms of erosion involving cutting, wear, plastic deformation wear and effect of temperature on erosion behaviour has been developed to predict erosion rates on the coal fired boiler components such as boiler tubes, economiser and air-preheater assembles at room & elevated temperature

A stochastic model for prediction of Erosion-oxidation interaction on boiler grade steel Surfaces

Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the flow path. Such erosion can reduce significantly the operational life of the boiler components. A fundamentally-derived mathematical model embodying the mechanisms of erosion involving cutting wear, plastic deformation wear and effect of temperature on erosion behaviour, has been developed to predict erosion rates on the coal fired boiler components such as boiler tubes, economizer and airpreheater assemblies at room and elevated temperature. Various grades of steels, commonly used in the fabrication of boiler components and published data pertaining boiler fly ash has been used for modelling the process. The model incorporates the tensile properties of the target metal surface at room and elevated temperatures, as well as the characteristics of the ash particle dynamics in the form of impingement angle, impingement velocity and composition of the ash particle in terms of the silica content. The mathematical model has been implemented in an userinteractive in-house computer code, (EROSIM–1 ) to predict the erosion rates at room and elevated temperature for various grades of steel normally used in boiler components. The model predictions have been found to be in good agreement with the published data. The model will be calibrated in future with the plant and experimental data generated from a high temperature air-jet erosion testing facility. It is hoped that the calibrated model will be useful to the power plant industry for erosion analysis of boiler components

Influence of varied crop residues and green biomass composts to rabi sorghum growing soils on uptake of major nutrients, microbial biomass and soil fertility status

A field experiment was conducted on vertisols (pH of 7.56 with organic carbon content of 0.55%) at Re- search Institute on Organic Farming, University of Agricultural Sciences, Raichur coming under northern Karnataka during rabi season of 2015-16 to study the Influence of varied crop residues and green biomass composts to rabi sorghum growing soils on uptake of major nutrients, organic carbon and soil fertility status. In general application of Cotton stalks, Redgram stalks, Glyricidia, combination of cotton and redgram stalks composts, FYM and combina- tion of organic and inorganic fertilizers helped to buildup soil nutrients with respect to organic carbon, available nitro- gen and phosphorus. Significantly higher nitrogen (227.3 kg ha-1), phosphorous (75.7 kg ha-1) and potassium (141.7 kg ha-1) uptake by rabi sorghum was recorded with combined application of recommended FYM (3 t ha-1) and NP fertilizers (50:25 kg N, P2O5 ha-1) (T14) followed by Cotton stalks +Redgram stalks + Glyricidia sp. with C:N ratio of 30:1 compost @ 50 kg N equivalent (T12: 222.0, 74.0 and 132.3 kg ha-1). The least uptake was recorded with abso- lute control (T15: 127.0, 42.0 and 71.7 kg ha-1). Similar trend was observed with organic carbon, available nitrogen and phosphorus. Combined application of recommended FYM (3 t ha-1) and NP fertilizers (50:25 kg N, P2O5 ha-1) followed by Cotton stalks +Redgram stalks + Glyricidia sp. with C:N ratio of 30:1 compost @ 50 kg N equivalent at the time of sowing recorded higher major nutrients uptake, microbial biomass and soil fertility status

Serine protease from Indian Cobra venom: its anticoagulant property and effect on human fibrinogen

An unusual low molecular weight serine protease (NnP28) has been purified from Indian Cobra (Naja naja) venom from the western region of the Indian sub-continent. We reported the purification and characterization of low molecular NnP28, emphasizing its role on human fibrinogen and anticoagulant property. NnP28 was purified using gel filtration column chromatography followed by ion exchange chromatography. Protein gel electrophoresis revealed its molecular weight approximate to 28 kDa. The exact molecular mass of NnP28 was found to be 27.12 kDa by mass spectrometry, hydrolyzing casein specifically, inhibited by PMSF suggesting it has a serine protease. NnP28 prolonged the clotting time of re-calcified human citrated plasma and activated partial thromboplastin time (APTT) exhibiting anticoagulant property. NnP28 exhibited fibrinogenolytic activity. Thus, the present study demonstrates the presence of unusual low molecular weight serine protease, emphasizing its importance of region-specific Indian cobra species

Barcoding of Asian seabass across its geographic range provides evidence for its bifurcation into two distinct species

Asian seabass or barramundi (Lates calcarifer) is an important food fish with commercial value and a wide geographic distribution. Though some reports based on molecular and/or morphological data exist, a comprehensive effort to establish species identity across its range is lacking. In order to address this issue and especially to ascertain whether the wide-spread distribution has resulted in bifurcation of the species, we collected Asian seabass samples from various locations representing the Western and Eastern Coastline of India, Andaman and Nicobar Islands, Bangladesh and Australia. Samples from Malaysia, Indonesia, Thailand and Singapore were collected as part of a previous study. DNA sequence variations, including cytochrome c oxidase subunit 1 (COI), 16S rDNA and the highly variable D-loop (or control region), were examined to establish species delineation. Data from all the sequences analyzed concordantly point to the existence of at least two distinct species—one representing the Indian subcontinent plus Myanmar, and a second, representing Southeast Asia (Singapore, Malaysia, Thailand and Indonesia) plus Northern Australia. These data are useful for conservation ecology, aquaculture management, for establishing the extent of genetic diversity in the Asian seabass and implementing selective breeding programs for members of this species complex

Implications of Extreme Climatic Events on Marine Fisheries Sector

Implications of Extreme Climatic Events on Marine Fisheries Secto