A simulation study of pearlite-to-austenite transformation kinetics in rapidly heated hot-rolled low carbon steel

The main aim of the present research was to obtain an optimized microstructure with adequate mechanical properties in a low carbon steel. The effect of microstructure on kinetics of austenite transformation was simulated. A 3.2 mm hot rolled steel was subjected to continuous annealing to obtain properties of Dual Phase 590 grade. Kinetics of austenite transformation was studied with respect to the condition of just pearlite dissolution to form austenite under rapid heating. Annealing parameters were based on process conditions of dual phase steel production in a continuous annealing line. DICTRA was used to simulate heating rates of the order 10–500 °C/s with peak temperatures in the range 750–850 °C to predict isothermal annealing time required for complete dissolution of pearlite into austenite under different temperature-heating rate conditions. Simulation results showed dependency of temperature and heating rate on austenite transformation time. Interestingly, no significant effect of heating rate on complete pearlite dissolution into austenite was evident. Results were validated with limited experimentation on Gleeble. Microstructure analysis validated the simulation results to be accurate. The observations have pertinent inputs while designing industrial continuous annealing line parameters where rapid heating rates are generally encountered (10–20 °C/s).A simulation study of pearlite-to-austenite transformation kinetics in rapidly heated hot-rolled low carbon steel (PDF Download Available). Availablefrom:https://www.researchgate.net/publication/303915593_A_simulation_study_of_pearlite-to austenite_transformation_kinetics_in_rapidly_heated_hot-rolled_low_carbon_steel [accessed Aug 14, 2017]

A Ring Shaped Embedded Young Stellar (Proto)Cluster

We present sub-arcsec (FWHM ~ 0.5") J, H, K and L' images of a young stellar cluster associated with a candidate massive protostar IRAS22134+5834. The observations reveal a centrally symmetric, flattened cluster enclosing a central dark region. The central dark region is possibly a cavity within the flattened cluster. It is surrounded by a ring composed of 5 bright stars and the candidate massive protostar IRAS22134+5834. We construct JHKL' color-color and HK color-magnitude diagrams to identify the young stellar objects and estimate their spectral types. All the bright stars in the ring are found to have intrinsic infrared excess emission and are likely to be early to late B type stars. We estimate an average foreground extinction to the cluster of A_v \~ 5mag and individual extinctions to the bright stars in the range A_v ~ 20-40mag indicating possible cocoons surrounding each massive star. This ring of bright stars is devoid of any HII region. It is surrounded by an embedded cluster making this an example of a (proto)cluster that is in one of the dynamically least relaxed states. These observations are consistent with the recent non-axisymmetric calculations of Li & Nakamura, who present a star formation scenario in which a magnetically subcritical cloud fragments into multiple magnetically supercritical cores, leading to the formation of small stellar groups.Comment: 13 pages in preprint format, 3 figures, 1 tabl

Differential regulation of cholera toxin-inhibited Na-H exchange isoforms by butyrate in rat ileum

Electroneutral Na absorption occurs in the intestine via sodium-hydrogen exchanger (NHE) isoforms NHE2 and NHE3. Bicarbonate and butyrate both stimulate electroneutral Na absorption through NHE. Bicarbonate- but not butyrate-dependent Na absorption is inhibited by cholera toxin (CT). Long-term exposure to butyrate also influences expression of apical membrane proteins in epithelial cells. These studies investigated the effects of short- and long-term in vivo exposure to butyrate on apical membrane NHE and mRNA, protein expression, and activity in rat ileal epithelium that had been exposed to CT. Ileal loops were exposed to CT in vivo for 5 h and apical membrane vesicles were isolated. 22Na uptake was measured by using the inhibitor HOE694 to identify NHE2 and NHE3 activity, and Western blot analyses were performed. CT reduced total NHE activity by 70% in apical membrane vesicles with inhibition of both NHE2 and NHE3. Reduced NHE3 activity and protein expression remained low following removal of CT but increased to control values following incubation of the ileal loop with butyrate for 2 h. In parallel there was a 40% decrease in CT-induced increase in cAMP content. In contrast, NHE2 activity partially increased following removal of CT and was further increased to control levels by butyrate. NHE2 protein expression did not parallel its activity. Neither NHE2 nor NHE3 mRNA content were affected by CT or butyrate. These results indicate that CT has varying effects on the two apical NHE isoforms, inhibiting NHE2 activity without altering its protein expression and reducing both NHE3 activity and protein expression. Butyrate restores both CT-inhibited NHE2 and NHE3 activities to normal levels but via different mechanisms

Small optic suspensions for Advanced LIGO input optics and other precision optical experiments

We report on the design and performance of small optic suspensions developed to suppress seismic motion of out-of-cavity optics in the Input Optics subsystem of the Advanced LIGO interferometric gravitational wave detector. These compact single stage suspensions provide isolation in all six degrees of freedom of the optic, local sensing and actuation in three of them, and passive damping for the other three

COMBINED ANALYSIS OF RADARSAT-2 SAR AND SENTINEL-2 OPTICAL DATA FOR IMPROVED MONITORING OF TUBER INITIATION STAGE OF POTATO

Tuber initiation and tuber bulking stages are critical part of various phenological phases for potato production. Tuber initiation covers the period from the formation of spherical rhizome ends, the flowering and the start of tuber bulking. In general, the tuberization spans from 3 to 5 weeks after emergence and ends with the row closer i.e. canopies in adjacent rows touch each other across the furrow. Hence, this rapid growth seeks critical agronomic management practices such as irrigation and fertilization. It majorly influences the growth of stems, foliar area, dry weight and number of tubers particularly at the phase of tuber initiation. During these phenological stages, potato crops are susceptible to the infestation of late blight diseases caused by Phytophthora infestans and largely affects the potato production. Thus identifying the crop risk using remote sensing approaches can provide an efficient potato growth monitoring framework. In the context of monitoring crop dynamics, quad-pol Synthetic Aperture Radar (SAR) data has proven to be effective due to its sensitivity towards dielectric and geometric properties. In addition to SAR data, optical remote sensing data derived vegetation information can provide an improved insight into crop growth when combined with SAR data. In this research, quad-pol RADARSAT-2 and Sentinel-2 optical data are analyzed to monitor potato tuberization phase over Bardhaman district in the state ofWest Bengal, which is one of the major potato growing regions in India. The proposed approach uses polarimetric parameters such as backscatter intensities, ratio (HH/VV, VH/VV, linear depolarization ratio), and co-pol correlation (ρHH–VV) along with the vegetation indices derived from the Sentinel-2 data for understanding the spatio-temporal dynamics. The initial results show a promising accuracy in monitoring the dynamics of potato tuberization. Integration of such earth observation (EO) data, in conjunction with in-situ field measurements, might significantly enhance the current capabilities for crop monitoring

Extensional collapse of the Gondwana orogen: evidence from Cambrian mafic magmatism in the Trivandrum Block, southern India

The assembly of Late Neoproterozoic–Cambrian supercontinent Gondwana involved prolonged subduction and accretion generating arc magmatic and accretionary complexes, culminating in collision and formation of high grade metamorphic orogens. Here we report evidence for mafic magmatism associated with post-collisional extension from a suite of gabbroic rocks in the Trivandrum Block of southern Indian Gondwana fragment. Our petrological and geochemical data on these gabbroic suite show that they are analogous to high Fe tholeiitic basalts with evolution of the parental melts dominantly controlled by fractional crystallization. They display enrichment of LILE and LREE and depletion of HFSE with negative anomalies at Zr–Hf and Ti corresponding to subduction zone magmatic regime. The tectonic affinity of the gabbros coupled with their geochemical features endorse a heterogeneous mantle source with collective melt contributions from sub-slab asthenospheric mantle upwelling through slab break-off and arc-related metasomatized mantle wedge, with magma emplacement in subduction to post-collisional intraplate settings. The high Nb contents and positive Nb–Ta anomalies of the rocks are attributed to inflow of asthenospheric melts containing ancient recycled subducted slab components and/or fusion of subducted slab materials owing to upwelling of hot asthenosphere. Zircon grains from the gabbros show magmatic crystallization texture with low U and Pb content. The LA-ICPMS analyses show 206Pb/238U mean ages in the range of 507–494 Ma suggesting Cambrian mafic magmatism. The post-collisional mafic magmatism identified in our study provides new insights into mantle dynamics during the waning stage of the birth of a supercontinent.Qiong-Yan Yang, Sohini Ganguly, E.Shaji, Yunpeng Dong, V. Nanda-Kuma

Insights on the Sun birth environment in the context of star-cluster formation in hub-filament systems

Cylindrical molecular filaments are observed to be the main sites of Sun-like star formation, while massive stars form in dense hubs, at the junction of multiple filaments. The role of hub-filament configurations has not been discussed yet in relation to the birth environment of the solar system and to infer the origin of isotopic ratios of Short-Lived Radionuclides (SLR, such as $^{26}$Al) of Calcium-Aluminum-rich Inclusions (CAIs) observed in meteorites. In this work, we present simple analytical estimates of the impact of stellar feedback on the young solar system forming along a filament of a hub-filament system. We find that the host filament can shield the young solar system from the stellar feedback, both during the formation and evolution of stars (stellar outflow, wind, and radiation) and at the end of their life (supernovae). We show that the young solar system formed along a dense filament can be enriched with supernova ejecta (e.g., $^{26}$Al) during the formation timescale of CAIs. We also propose that the streamers recently observed around protostars may be channeling the SLR-rich material onto the young solar system. We conclude that considering hub-filament configurations as the birth environment of the Sun is important when deriving theoretical models explaining the observed properties of the solar system.Comment: Accepted for publication in The Astrophysical Journal Letter

Beneficial health effects of cumin (Cuminum cyminum) seeds upon incorporation as a potential feed additive in livestock and poultry: A mini-review

Cumin (Cuminum cyminum Linn) is an annual plant of the family Umbelliferae, with its use dating back to ancient times when it was cultivated for its medicinal and culinary potential. Cumin seeds could contain a wide variety of phytochemicals, including alkaloids, coumarins, anthraquinones, flavonoids, glycosides, proteins, resins, saponins, tannins, and steroids. In particular, linoleic acid, one of the unsaturated fatty acids found in abundance in cumin oleoresin, is credited with promoting good health. Many of cumin's purported biological actions in livestock and poultry have been attributed to flavonoids such as apigenin, luteolin, and glycosides. Cumin has several healthful qualities, such as antibacterial, insecticidal, anti-inflammatory, analgesic, antioxidant, anticancer, anti-diabetic, anti-platelet aggregation, hypotensive, bronchodilatory, immunological, anti-amyloidogenic, and anti-osteoporotic properties. Cumin supplementation may improve milk production and reproductive function in dairy cows by altering the feeding pattern of bacteria in the rumen, encouraging the growth of beneficial microbes, or stimulating the secretion of certain digestive enzymes. Because of the low price of cumin seed, it could be concluded that its inclusion in the diet might be beneficial to the commercial poultry industry and reduce the overall cost of egg and meat production. In recent years a rise in cumin's popularity has been seen as a result of the herbal movement spearheaded by naturopaths, yoga gurus, advocates of alternative medicine, and manufacturers of feed additives. Animal nutritionists are exploring the use of cumin for its potential to boost growth, improve nutrient usage efficiency, and reduce greenhouse gas emissions. This mini-review discusses how cumin could be used as a feed ingredient to boost productivity and ensure healthy animal reproduction