Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 ...terrestrial biosphere models for the Alaskan Arctic from four recent model intercomparison projects – NACP (North American Carbon Program) site and regional syntheses, TRENDY (Trends in net land atmosphere carbon exchanges), and WETCHIMP (Wetland and Wetland CH4 Inter-comparison of Models Project) – we provide a baseline of terrestrial carbon cycle uncertainty, defined as the multi-model standard deviation (σ) for each quantity that follows. Mean annual absolute uncertainty was largest for soil carbon (14.0 ± 9.2 kg C m−2), then gross primary production (GPP) (0.22 ± 0.50 kg C m−2 yr−1), ecosystem respiration (Re) (0.23 ± 0.38 kg C m−2 yr−1), net primary production (NPP) (0.14 ± 0.33 kg C m−2 yr−1), autotrophic respiration (Ra) (0.09 ± 0.20 kg C m−2 yr−1), heterotrophic respiration (Rh) (0.14 ± 0.20 kg C m−2 yr−1), net ecosystem exchange (NEE) (−0.01 ± 0.19 kg C m−2 yr−1), and CH4 flux (2.52 ± 4.02 g CH4 m−2 yr−1). There were no consistent spatial patterns in the larger Alaskan Arctic and boreal regional carbon stocks and fluxes, with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic and larger boreal region.
► Beneficiation of −3+0.3mm size fraction non-coking coal using jig was studied. ► Effects of particle sizes of bed material and particle sizes of coal were studied. ► Effects of feed rate and water ...rate on the performance of the jig were studied. ► ANN model was proposed to predict ash and combustible recovery of the concentrate.
Non-coking coal is the major resource of energy in India. Apart from its utilization in energy sector, the other major application of this coal is in metallurgical sector. The resource of high quality of non-coking coal is not available as per demand; as a result beneficiation of non-coking coal is now becoming essential. Jigging is one of the economical physical beneficiation processes for Indian high ash non-coking coal. At present scenario in coal washery in India, below 3mm size is not being processed. Attempt has been taken to beneficiate the fine size non-coking coal fractions generated at different sizes of bed materials, feed rates and water rates using laboratory Denver mineral jig. The performance of jig was evaluated in term of Ep and imperfection value. Furthermore artificial neural network (ANN) model has been developed for determining combustible recovery and ash percent of the concentrate. The ANN architecture is made up of three layers (input – hidden – output). A back propagation algorithm was used for training of the ANN model. It has been observed that the predicted values by ANN model are in good agreement with the experimental results.
•Water stress in wheat has been characterized using spectral indices.•Validation of spectral index model was done for prediction of grain and biomass yield of wheat.•Models based on the spectral ...indices, NWI-1 and WI recorded at milk stage can predict the grain and biomass yield of wheat.
There is a need to characterize the water stress in wheat using suitable indices, which will help us to find out the water stress sensitive period for efficient use of irrigation water. Recently indices based on canopy spectral reflectance, which are non destructive, fast and reliable, are being used effectively to characterize the water stress. A field experiment was carried out during the year 2010–2012 in split plot design with four levels of irrigation (irrigation at 0.4 IW/CPE, 0.6 IW/CPE, 0.8 IW/CPE and 1.0 IW/CPE, IW=6cm) as main plot factors and three sources of nitrogen (100%N from urea, 50% N from urea and 50% N from farmyard manure (FYM) and 100% N from FYM) as subplot factors. The objective of the study was to find out the water stress indices best correlated with wheat grain and biomass yield, to determine the optimum growth stage for measurement of water stress indices and to predict the grain and biomass yield of wheat based on water stress indices. The canopy reflectance was measured in the spectral range of 350–2500nm with 1nm bandwidth with the help of hand held ASD FieldSpec Spectroradiometer at seven phenostages, viz., crown root initiation (CRI), tillering, booting, flowering, milk, soft dough and harvesting stage. Then different water stress indices were computed as: water index (WI)=R970/R900, normalized water index-1 (NWI-1)=(R970−R900)/(R970+R900), normalized water index-2 (NWI-2)=(R970−R850)/(R970+R850), normalized water index-3 (NWI-3)=(R970−R920)/(R970+R920), normalized water index-4 (NWI-4)=(R970−R880)/(R970+R880), where R and the subscript numbers indicate the light reflectance at the specific wavelength (in nm). It was observed that spectral reflectance based water indices recorded at the milk stage, WI and NWI-1 were significantly negatively correlated with the grain yield and NWI-1 and NWI-3 were significantly negatively correlated with the biomass yield of wheat, having maximum correlation coefficients. Validation of regression model based on NWI-1 could account for the maximum 87.5% variation in the observed grain yield and the regression model based on WI could account for maximum 89.2% variation in the observed biomass yield of wheat with minimum root mean square errors. So the regression models based on NWI-1 and WI recorded at milk stage can be successfully used to predict the grain and biomass yield of wheat in advance.
•Impact of defect-dipoles on dielectric and optical behavior are investigated systematically.•Grain and grain boundary barrier properties play a decisive role to attain unparalleled dielectric ...behavior in materials.•It was established that the growth of grain boundary barrier confines the mobile charge carrier into the grain.•Such confinement leads to localized transport not only brings high dielectric constant but also reduces the dielectric loss.•Interestingly, La/Nd doping induces exotic ferroelectric behavior into quantum paraelectric SrTiO3.•Nevertheless, superior optical properties and reduced bandgap can also be achieved in La/Nd coped SrTiO3 system.
Defect-dipole and defect-clusters provide a novel paradigm to realize unprecedented dielectric behavior along with ultralow dielectric loss, in any ordinary dielectric material. In the present work, with the help of the La/Nd co-doped SrTiO3 (STO) system, it has been shown that the type, nature, and localization of these defect dipoles and clusters play a significant role in controlling the dielectric behavior. Polycrystalline ceramic samples of La0.1Sr0.9−xNdxTiO3 (x = 0.05, 0.07, 0.09, 0.11) are synthesized by mechanical alloying followed by high temperature solid-state reaction techniques. Investigations of structural and microstructural properties are carried out by using the X-ray diffraction technique and scanning electron microscopy, respectively. The dielectric and electrical parameters are studied in a frequency ranging from 1 kHz to 1 MHz and the temperature ranging from 30 °C to 450 °C. The results demonstrate that all the synthesized samples exhibit single-phase perovskite structure with Pm3̅m space group. Though STO displays quantum paraelectric behavior, intriguingly, all the La/Nd doped STO samples exhibit ferroelectric behavior with the dielectric maximum increasing with the increase in the doping concentration. The superior dielectric behavior in the doped samples is ascribed to the suppression of grain boundary conductivity due to the formation of a double Schottky barrier (due to VSr′′/Vo••) and enhancement of grain conductivity due to localized transport involving defect dipoles/clusters within the grain. Interestingly, the presence of VSr′′andVo•• has been supported by the photoluminescence analysis. Nevertheless, La/Nd doping results in a systematic reduction in the band gap.
With increasing demand for accurate calculation of isotope shifts of atomic systems for fundamental and nuclear structure research, an analytic energy derivative approach is presented in the ...relativistic coupled-cluster (CC) theory framework to determine the atomic field shift and mass shift (MS) factors. This approach allows the determination of expectation values of atomic operators, overcoming fundamental problems that are present in existing atomic physics methods, i.e. it satisfies the Hellmann-Feynman theorem, does not involve any non-terminating series, and is free from choice of any perturbative parameter. As a proof of concept, the developed analytic response relativistic CC theory has been applied to determine MS and field shift factors for different atomic states of indium. High-precision isotope-shift measurements of 104 − 127 In were performed in the 246.8 nm (5p 2P3/2 → 9s 2S1/2) and 246.0 nm (5p 2P1/2 → 8s 2S1/2) transitions to test our theoretical results. An excellent agreement between the theoretical and measured values is found, which is known to be challenging in multi-electron atoms. The calculated atomic factors allowed an accurate determination of the nuclear charge radii of the ground and isomeric states of the 104 − 127 In isotopes, providing an isotone-independent comparison of the absolute charge radii.
The EXAFS technique, which deals with fine structure oscillations observed in the X-ray absorption spectrum of an element from 50 eV to ~700 eV above its absorption edge, gives precise information ...regarding the short range order and local structure around the particular atomic species in the material. With the advent of modern bright synchrotron radiation sources, EXAFS has emerged to be the most powerful local structure determination technique, which can be applied to any type of material viz. amorphous, polycrystalline, polymers, surfaces and solutions etc. Over the last few years a comprehensive facility for carrying out EXAFS measurements with synchrotron radiation over variety of samples has been developed at the 2.5 GeV, Synchrotron Radiation Source (INDUS-2) at RRCAT, Indore, India. The facility consists of two operational beamlines viz., the energy dispersive EXAFS beamline (BL-08) and the Energy Scanning EXAFS beamline (BL-09).
Pre-straining at different strain-rate is usually carried out during forming of 304L stainless steel (SS) which can affect its corrosion behaviour. A systematic study on the effect of strain-rate in ...conjunction with pre-strain on electrochemical corrosion behaviour of 304L SS is elucidated for the first time. Prior deformation (10% and 30%) resulted in either beneficial or detrimental effect on the corrosion and pitting resistance depending up on the imposed strain-rate. A novel observation of improved corrosion resistance at higher strain-rate is attributed to differences in strain-rate dependent evolution of microstructure and substructure. This work suggests that the corrosion behaviour of 304L SS is a stronger function of strain-rate compared to the strain and from the microstructure viewpoint, it depends on the complex interplay between dislocation density, deformation-induced martensite, coincidence site lattice (CSL) boundary and, crystallographic texture.
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•Novel observation on the domination role of strain-rate on corrosion behavior of 304L SS is demonstrated.•Corrosion behavior was studied using Potentiodynamic Polarization and EIS tests.•Higher dislocation density and deformation-induced martensite are detrimental for pitting resistance.•CSLboundaries and crystallographic texture close to end orientation are favourable for pitting resistance.•Overall pitting resistance depends on the complex interplay of microstructure, dislocation density and texture.
To determine if the innate immunity of Asian catfish (
Clarias batrachus) raised in captivity are affected by the rearing temperature or seasons, various indices of the humoral and cellular innate ...immune functions were measured in fish reared at a wide range of water temperatures over a period of 2 years. Measures of humoral immunity included the estimation of serum myeloperoxidase, lysozyme, haemagglutinin and alternative complement activities. Cellular assay quantified the ability of blood phagocytes to mount superoxide production. Fish were sampled during different periods of two consecutive years, maintained at similar prevailing ranges of water temperature. Experiments were performed at mean temperatures of 19, 24, 28, 31, 32.5 °C during the same time of 2 years. The kinetics of the temperature or season mediated immunomodulation in the innate immune parameters was remarkably fluctuated among the individuals and at different periods or temperatures. Although a clear seasonal variation was marked in the innate immune parameters of this species, the fluctuations of all the parameters are not consistent to any of the temperatures except for lysozyme levels that remained significantly lower during summer compared to other seasons. The probable compensatory mechanism among the innate defence molecules might be playing role to protect from infections during different water temperatures or seasons.
The present study demonstrates the spatial analysis and mapping of fish and different measures of environmental parameters and fish diversity of Pong reservoir, Himachal Pradesh, using Kriging ...spatial interpolation methods for geographical information system mapping. Seasonal data on environmental parameters, potential fish habitat and fish diversity was collected from lentic (dam), lentic (reservoir), transitional and lotic zone of the reservoir.. Important environmental parameters like water temperature, dissolved oxygen, electrical conductivity, water depth and transparency showed variations across the different zones of the reservoir. The sediment of the reservoir was sandy clay loam in nature as per texture analysis. Fish species richness, Shannon index and evenness index showed a similarity of the lotic and lentic (reservoir) zones of the reservoir. Six potential fish breeding grounds were identified in the reservoir indicating high conservation significance. The analysis of data showed a declining trend in fish production from 456.9 tonnes during the decade 1976–1987 to 347.91 tonnes during 2009–2020. The factors like anthropogenic climate change, predation of a stocked fish juvenile by water birds, undersized fish stocking and unscientific management are the probable reasons for the decreasing fish production. The spatial variation pattern of the water spread area, environmental parameters, fish catch and potential fish breeding grounds depicted in the GIS platform can be used as an important information base by the policy makers for fisheries management. The stocking of large size fish as a stocking material and adequate protection of the potential fish breeding grounds are the key advisories for the sustainable enhancement of fisheries as well as conservation.
Bismuth magnesium oxide (BMO) thin films were prepared by an unconventional sol-gel method and the films deposited on glass slides were annealed at 60 °C and 120 °C. XRD reveals the single-phase ...nature of the synthesized material. The morphological characterization of the samples was carried out with SEM and optical characterization was performed with UV-Vis spectroscopy in the wavelength range 300 to 850 nm. The fundamental optical parameters like refractive index, optical conductivity, and extinction coefficient were calculated from the UV-Vis absorption spectra. The Bandgap for both the BMO thin films annealed at 60 °C and 120 °C were obtained as 3.26 eV and 3.29 eV, respectively. Also, this study covered the measurements of the complex dielectric function and depending on this, the interband transition strength, the surface energy loss function (SELF) and the volume energy loss function (VELF) were also obtained. The results obtained in this study are compared with available literature and it was found that parameters like refractive index, extinction coefficient, band gap etc. in our study are better than that reported by other researchers.
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Highlights
The material is synthesized by an unconventional sol gel technique which is cost effective and easy to fabricate.
Obtained optical parameters are better than that reported earlier.
Optical properties of the materials indicate suitable applications of the synthesized thin films.
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