Characteristics of superplasticity domain in the processing map for hot working of as-cast Mg–11.5Li-1.5Al alloy

Processing map for hot working of as-cast Mg-11.5Li-1.5Al alloy has been developed in the temperature range 200–450°C and strain rate range 0.001-100 s−1. The map exhibited a single domain with a peak efficiency of 65% occurring at 400°C and 0.001 s−1. Under these conditions, the material exhibited abnormal elongation. On the basis of the elongation, the grain structure, the apparent activation energy for hot deformation (95 kJ mole−1) and the peak efficiency of power dissipation (65% corresponding to a strain rate sensitivity of about 0.5), the domain is interpreted to represent superplasticity. At strain rates higher than about 10 s−1, the material exhibits microstructural instability, while at temperatures of 450°C and a strain rate of 0.001 s−1, grain boundary cracking is observed

Processing map for hot working of alpha-zirconium

The hot deformation characteristics of alpha-zirconium in the temperature range of 650°C to 850°C and in the strain-rate range of 10-3 to 102 s-1 are studied with the help of a power dissipation map developed on the basis of the Dynamic Materials Model. The processing map describes the variation of the efficiency of power dissipation (η=2m/m + 1) calculated on the basis of the strain-rate sensitivity parameter (m), which partitions power dissipation between thermal and microstructural means. The processing map reveals a domain of dynamic recrystallization in the range of 730°C to 850°C and 10-2 to 1-1 with its peak efficiency of 40 pct at 800°C and 0.1 s-1 which may be considered as optimum hot-working parameters. The characteristics of dynamic recrystallization are similar to those of static recrystallization regarding the sigmoidal variation of grain size (or hardness) with temperature, although the dynamic recrystallization temperature is much higher. When deformed at 650°C and 10-3 s-1 texture-induced dynamic recovery occurred, while at strain rates higher than 1 s-1, alpha-zirconium exhibits microstructural instabilities in the form of localized shear bands which are to be avoided in processing

Chemical Constituents during the Main and Off-Season in Mango (Mangifera indica L.) Cv. Royal Special

Evaluation and quantification of fruit quality parameters like carbohydrates, phenolics, flavonoids, ascorbic acid, titrable acidity, Total Soluble Solids (TSS), carotenoids and lycopene content was done in fruits of mango cv. Royal Special, at ICAR-Indian Institute of Horticultural Research, Bengaluru, India, during the off-season (October, 2012) and main-season (June, 2013), respectively. 'Royal Special' is a typical off-season bearing cultivar, often characterized by multiple flushing and flowering under South Indian conditions. Major phytonutrients such as total sugars, reducing sugars, starch, total carotenoids, lycopene, total phenols, flavonoids, ascorbic acid, TSS, titrable acidity and average fruit yield per plant, were recorded during the off- and main- seasons. Results indicated that fruits from off-season were higher in the major chemical constituents studied compared to the main-season crop, except for fruit yield per plant. This may be attributed to poor competition for nutrients among the developing fruits which act as a sink, besides fluctuating environmental conditions during the off-season, compared to the main-season

Effect of stacking fault energy on the dynamic recrystallization during hot working of FCC metals: a study using processing maps

The influence of stacking fault energy (SFE) on the mechanism of dynamic recrystallization (DRX) during hot deformation of FCC metals is examined in the light of results from the power dissipation maps. The DRX domain for high SFE metals like Al and Ni occurred at homologous temperature below 0·7 and strain rates of 0·001 s−1 while for low SFE metals like Cu and Pb the corresponding values are higher than 0·8 and 100 s−1. The peak efficiencies of power dissipation are 50% and below 40% respectively. A simple model which considers the rate of interface formation (nucleation) involving dislocation generation and simultaneous recovery and the rate of interface migration (growth) occurring with the reduction in interface energy as the driving force, has been proposed to account for the effect of SFE on DRX. The calculations reveal that in high SFE metals, interface migration controls DRX while the interface formation is the controlling factor in low SFE metals. In the latter case, the occurrence of flow softening and oscillations could be accounted for by this model

Model simulation of tide-induced currents in Gauthami-Godavari estuary

Predictive spatial distribution of flow field has been simulated from the time series data on currents and tides during dry season (11-19, February, 2009) in the Gauthami-Godavari Estuary utilizing TIDAL model. A 2D-Tidal Estuarine model has been considered (instead of 3D model) due to well-mixed type system and its circulation is dominated by tides during the observational period. The model forcing functions consist of wind and tidal elevations along the open boundaries and no fresh water inflow from the main stream and no land flood in river system. The bathymetry data of the river basin has been collected and supplemented to the model as one of the rigid boundary conditions to evaluate integration. The bottom roughness length (K) was adjusted to achieve model calibration and verification in model simulations of flow field. The model simulation results are in qualitative agreement with the observational data with calibrated bottom roughness length which is about 0.085 m. Model results reveal that the majority of flow was found to be along the channel axis (i.e. high iso-bath contour). During flood time, flow is south-west direction and it is changed to northeast direction during ebb period which is indicating that the model results resemble flow in the real eastern system

Spontaneous emission of an atom placed near a nanobelt of elliptical cross-section

Spontaneous emission of an atom (molecule) placed near a nanocylinder of elliptical cross-section of an arbitrary composition is studied. The analytical expressions have been obtained for the radiative and nonradiative channels of spontaneous decay and investigated in details.Comment: 35 pages, 11 figure

Assessing village-level carbon balance due to greenhouse gas mitigation interventions using EX-ACT model

Under National Initiative on Climate Resilient Agriculture (NICRA) project, a range of climate smart agricultural practices were evaluated with on-farm demonstrations during 2011–2013 in eight climatically vulnerable villages of Andhra Pradesh, India. Proven climate smart practices viz residue recycling, soil, water and nutrient management, afforestation and feeding + breeding practices in livestock were implemented in annual and perennial crops, irrigated rice, horticulture, fodder, forestry and livestock. An EX-ante carbon-balance tool (EX-ACT) developed by the FAO was used with a combination of various climate smart interventions to know the mitigation potentials in eight climatically vulnerable villages of Andhra Pradesh, India. Based on our observations, EX-ACT model had shown that these practices were effective to mitigate CO2 emissions apart from enhancing soil productivity. In Nacharam, Yagantipalli, Sirusuwada and Matsyapuri villages, climate smart practices implemented in annual crops along with crop residue recycling, crop and water management practices resulted in negative carbon (C) balance by −16,410, −8851, −7271 and −6125 t CO2 e, respectively. The EX-ACT model predicted positive carbon balance with irrigated module in the rice-growing villages of Sirusuwada and Matsyapuri villages. The negative values suggest a sink, and positive values a source for CO2 emissions. In Chamaluru village, although there were CO2 emissions (source) due to livestock and non-forest and land use changes, there was a carbon sink due to other activities as predicted by the model. The results suggested that various climatic smart practices at the village level were successful in creating net sink of CO2 emissions (t CO2 e)

Variability in stratification and flushing times of the Gautami–Godavari estuary, India

In order to examine the influence of forcing (river flow and tides) and anthropogenic activities (dredging and dam regulation) on stratification, a study was conducted over a period of 19 months (June 2008–December 2009) in the Gautami–Godavari estuary (G–GE) during spring and neap tide periods covering entire spectrum of discharge over a distance of 36 km from the mouth. The bathymetry of the estuary was recently changed due to dredging of ∼20 km of the estuary from the mouth for transportation of barges. This significantly changed the mean depth and salinity of the estuary from its earlier state. The variations in the distribution of salinity in the Godavari estuary are driven by river discharge during wet period (June–November) and tides during dry period (December–May). The weak stratification was observed during high discharge (July–August) and no discharge (January–June) periods associated with dominant fresh water and marine water respectively. The strong stratification was developed associated with decrease in discharge during moderate discharge period (October–December). Relatively stronger stratification was noticed during neap than spring tides. The 15 psu isohaline was observed to have migrated ∼2–3 km more towards upper estuary during spring than neap tide suggesting more salt enters during former than latter period. Total salt content was inversely correlated with river discharge and higher salt of about 400×106 m3 psu was observed during spring than neap tide. Flushing times varied between less than a day and more than a month during peak and no discharge periods respectively with lower times during spring than neap tide. The flushing times are controlled by river discharge during high discharge period, tides during dry period and both (river discharge and tides) under moderate discharge period. This study suggests that modification of discharge, either natural due to weak monsoon or artificial such as dam constructions and re-routing the river flow, may have significant impact on the stratification and biogeochemistry of the Godavari estuary

Quantification of Dhurrin in Different Types of Sorghum Forages by Near-Infrared Reflectance Spectroscopy

Hydrogen cyanide (HCN) is a toxic chemical that can potentially cause mild to severe reactions in animals upon feeding forage sorghum. Developing technologies to monitor the level of HCN in the growing crop could prevent livestock poisoning. In this study ncar-infrared spectroscopy (NIRS) calibration to estimate HCN in forage sorghum is developed. The full spectral NIRS range (1100-2498 nm) was used as well as specific spectral ranges within the full spectral range, i.e. , visible (400-750 nm), short wave (800-1100 nm) and near - infrared (NIR) (1100-2498 nm). Using the full spectrum approach and the modified partial least-squares (MPLS), the calibration produced a coefficient of determination (R2) = 0.869 and standard error of cross-validation (SFCV) = 97.53%, while the validation set had a R2=0.624 with a low standard error of prediction (SEP= 205.801 %)

Intermittency transitions to strange nonchaotic attractors in a quasiperiodically driven Duffing oscillator

Different mechanisms for the creation of strange nonchaotic attractors (SNAs) are studied in a two-frequency parametrically driven Duffing oscillator. We focus on intermittency transitions in particular, and show that SNAs in this system are created through quasiperiodic saddle-node bifurcations (Type-I intermittency) as well as through a quasiperiodic subharmonic bifurcation (Type-III intermittency). The intermittent attractors are characterized via a number of Lyapunov measures including the behavior of the largest nontrivial Lyapunov exponent and its variance as well as through distributions of finite-time Lyapunov exponents. These attractors are ubiquitous in quasiperiodically driven systems; the regions of occurrence of various SNAs are identified in a phase diagram of the Duffing system.Comment: 24 pages, RevTeX 4, 12 EPS figure