Understanding the spatial spreading patterns of plant-available sulphur (S) (AS) and plant-available micronutrients (available zinc (AZn), available iron (AFe), available copper (ACu), available ...manganese (AMn) and available boron (AB)) in soils, especially in coastal agricultural soils subjected to various natural and anthropogenic activities, is vital for sustainable crop production by adopting site-specific nutrient management (SSNM) strategies. We studied the spatial distribution patterns of AS, AZn, AFe, ACu, AMn, and AB in cultivated soils of coastal districts of India using geostatistical approaches. Altogether 39,097 soil samples from surface (0 to 15 cm depth) layers were gathered from farm lands of 68 coastal districts. The analysis of soil samples was carried out for soil pH, electrical conductivity (EC), soil organic carbon (SOC) and AS, AZn, AFe, ACu, AMn, and AB. Soil pH, EC and SOC varied from 3.70 to 9.90, 0.01 to 7.45 dS m.sup.-1 and 0.02 to 3.74%, respectively. The concentrations of AS, AZn, AFe, ACu, AMn, and AB varied widely in the study area with their corresponding mean values were 37.4±29.4, 1.50±1.53, 27.9±35.1, 2.14±1.74, 16.9±18.4 and 1.34±1.52 mg kg.sup.-1, respectively. The coefficient of variation values of analyzed soil parameters varied from 14.6 to 126%. The concentrations of AS, AZn, AFe, ACu, AMn, and AB were negatively and significantly correlated with soil pH and positively and significantly correlated with SOC. The geostatistical analysis indicated stable, Gaussian and exponential best-fit semivariogram models with moderate to strong spatial dependence for available nutrients. The generated spatial spreading maps revealed different distribution patterns for AS, AZn, AFe, ACu, AMn, and AB. There were variations in spatial spreading patterns of AS, AZn, AFe, ACu, AMn, and AB in east- and west-coastal area. About 62, 35, 12, 0.4, 23 and 45% of the study area had deficiency of AS, AZn, AFe, ACu, AMn, and AB, respectively. The spatial spreading maps will be highly useful for SSNM in the cultivated coastal soils of the country. This study could also be used as a base for assessing spatial spreading patterns of soil parameters in cultivated coastal areas of other parts of the world.
Protein, starch, amylose and total soluble sugars are basic metabolites of seed that influence the eating, cooking and nutritional qualities of rice. Chlorophyll is responsible for the absorption and ...utilization of the light energy influencing photosynthetic efficiency in rice plant. Mapping of these traits are very important for detection of more number of robust markers for improvement of these traits through molecular breeding approaches.
A representative panel population was developed by including 120 germplasm lines from the initial shortlisted 274 lines for mapping of the six biochemical traits using 136 microsatellite markers through association mapping. A wide genetic variation was detected for the traits, total protein, starch, amylose, total soluble sugars, chlorophyll a, and chlorophyll b content in the population. Specific allele frequency, gene diversity, informative markers and other diversity parameters obtained from the population indicated the effectiveness of utilization of the population and markers for mapping of these traits. The fixation indices values estimated from the population indicated the existence of linkage disequilibrium for the six traits. The population genetic structure at K = 3 showed correspondence with majority of the members in each group for the six traits. The reported QTL, qProt1, qPC6.2, and qPC8.2 for protein content; qTSS8.1 for total soluble sugar; qAC1.2 for amylose content; qCH2 and qSLCHH for chlorophyll a (Chl. a) while qChl5D for chlorophyll b (Chl. b) were validated in this population. The QTL controlling total protein content qPC1.2; qTSS7.1, qTSS8.2 and qTSS12.1 for total soluble sugars; qSC2.1, qSC2.2, qSC6.1 and qSC11.1 for starch content; qAC11.1, qAC11.2 and qAC11.3 for amylose content; qChla8.1 for Chl. a content and qChlb7.1 and qChlb8.1 for Chl. b identified by both Generalized Linear Model and Mixed Linear Model were detected as novel QTL. The chromosomal regions on chromosome 8 at 234 cM for grain protein content and total soluble sugars and at 363 cM for Chl. a and Chl. b along with the position at 48 cM on chromosome 11 for starch and amylose content are genetic hot spots for these traits.
The validated, co-localized and the novel QTL detected in this study will be useful for improvement of protein, starch, amylose, total soluble sugars and chlorophyll content in rice.
Tropical Cyclone Heat Potential (TCHP) is the heat content relative to 26°C isotherm, which is important in the development of cyclone. Cyclonic events last for few weeks and become intensified ...within few days or in some cases few hours. To study such low pressure systems, daily TCHP is required which is created in our study using Two Layer Gravity Model (TLGM) using monthly climatologies of temperature and salinity profiles, daily Sea Surface Height Anomaly (SSHA) and daily Sea Surface Temperature (SST). This satellite-based data of SSHA and SST are used to create daily TCHP fields which are validated using collocated ARGO in-situ data. ARGO derived TCHP and TLGM TCHP showed correlation coefficient
, which indicates that TLGM can be used for near real time TCHP calculation for cyclone studies. Analysis done on 92 non-developing and 93 developing systems shows that, on the day of formation of depression, average TCHP is 89.3 kJ cm
for developing systems while average TCHP is 78.3 kJ cm
for non-developing systems in North Indian Ocean (NIO). Minimum TCHP was found to be 27.2 kJ cm
and 28.6 kJ cm
for developing and non developing systems out of 93 and 92 cases, respectively. Further, Genesis Potential Parameter (GPP) using low-level relative vorticity, middle troposphere relative humidity, middle troposphere temperature instability and vertical wind shear is created based on past similar studies, but with six hourly as well as daily resolution (1993 to 2017) and 0.125
°
0.125
°
spatial resolution. Using daily TCHP, another index called Genesis Potential Index (GPI) is created and then both the GPP and GPI are analysed for 93 developing and 92 non-developing systems in north Indian ocean from the year 1993 to 2017. Our study shows that both are good predictors for the lead periods of less than 2 days, while for the lead periods of more than 2 days, the distinction becomes difficult between developing and non-developing systems.
Abbreviations: TLGM - Two Layer Gravity Model; TCHP - Tropical Cyclone Heat Potential;
- Depth of 26°C isotherm;
- Depth of 20°C isotherm; NIO - North Indian Ocean; AS - Arabian Sea; India Meteorological Department - IMD; BOB - Bay of Bengal
A numerical study is made on the mixed convection of copper–water nanofluid inside a differentially heated skew enclosure. Co-ordinate transformations are used to transform the physical domain to the ...computational domain in an orthogonal co-ordinate. The finite volume based SIMPLEC algorithm is used to solve the transformed equations for fluid flow and heat transfer equations in the computational domain. The fluid flow and heat transfer characteristics are studied for a wide range of skew angles (30°⩽λ⩽150°), nanoparticle volume fraction (0.0⩽ϕ⩽0.2) and Richardson number (0.1⩽Ri⩽5) at a fixed value of Reynolds number. The entropy generation and Bejan number are evaluated to demonstrate the thermodynamic optimization of the mixed convection. It is shown that the heat transfer rate increases remarkably by the addition of nanoparticles. The flow field is sensible to the skew angle variation. Our results show that the heat transfer augmentation through nanoparticles with lower rate in entropy generation enhancement can be achieved in a skewed cavity.
Winter-to-early spring non-monsoonal precipitation over the Western Himalayas (WH) primarily comes from eastward propagating synoptic-scale weather systems known as western disturbances (WDs). ...Earlier studies have noted that an increasing trend of synoptic-scale WD activity in the past few decades has contributed to enhanced propensity of daily precipitation extremes over the WH, although it remains unclear as to whether these regional changes are manifestations of climate change. This issue is addressed by conducting a suite of long-term climate experiments using a global variable-grid climate model with high-resolution telescopic zooming over the South Asian region. Our findings highlight that human-induced climate change has implications on the rising trend of synoptic-scale WD activity and precipitation extremes over the WH during the recent few decades, and these changes cannot be explained by natural forcing alone. A stronger surface warming, in response to climate change, is noted over the vast expanse of the high-elevated eastern Tibetan Plateau relative to the western side. The model simulations show that strengthening of positive east–west temperature gradient across the Tibetan Plateau tends to alter the background mean circulation in a manner as to favor amplitude enhancements of the synoptic-scale WDs and orographic precipitation over the WH. With continuation of global warming in future and enhancement in the east–west temperature gradient across the Tibetan highlands, the trend of precipitation extremes over the WH and synoptic-scale WD activity are projected to rise into the twenty-first century. While the high-resolution simulations of this study offers promising potential to understand changes in synoptic-scale WD activity and precipitation extremes over the WH, further investigations are necessary to decipher the multi-scale behavior and intricacies of the Himalayan precipitation variability under changing climate.
•Performance study on jet plate solar air heater is presented.•Outlet air temp decreases and efficiency increases with increase in mass flow rate.•Nusselt number increases with increase of Reynolds ...number for Z2 (0.06m and 0.07m).•Maximum increment in Nusselt number is found as 76.1% at higher Z2 than lower Z1.•Correlation shows that the Reynolds no. has stronger effect on Nusselt no.
The present work deals with the experimental study of effects of flow and channel spacings, Z1 and Z2 on the performance of a cross – flow staggered hole jet plate solar air heater. This work is carried out with mass flow rate, ṁ1=0.030–0.065kg/s, ṁ2=0.020–0.043kg/s, Reynolds number, Re=2700–6900, depth ratio, Z2/Z1=0.75–1.0, total air depth, Z=0.14m, jet hole diameter, D=0.006m, Number of jet holes, N=1173 and tilt angle, θ=22.6°. The experiment is performed during the month of November - December, 2013 at ISM Dhanbad, India between 9.00 AM to 3.00 PM on hourly basis in the clear sky with the help of precision instruments fitted with the setup for recording the temperature, velocity and intensity of radiation. The performance in terms of outlet temperature, collector efficiency and Nusselt no. of this solar air heater are found substantially higher at higher spacing between the jet and absorber plate (Z2=0.07m) while mass flow rate adversely affects the outlet temperature. In the present study, the non-conventional jet plate solar air heater is also compared with conventional parallel plate solar air heater and it is observed that the performance of the jet plate solar air heater is always higher than conventional solar air heater. Friction factor is not significantly changed with Z2. Based on the experimental data, the correlations for Nusselt number and friction factor have been developed.
•Mixed convection heat transfer of a Cu-water nanofluid is considered.•A differentially heated skewed enclosure is considered.•Brownian and thermophoretic diffusions are considered.•The governing ...equations along with the boundary conditions are solved using a finite volume.•It is shown that the Brownian and thermophoretic diffusions have relatively negligible effects.
A non-homogeneous model in which the nanoparticles have relative velocity compared to the based fluid is considered to study the convective heat transfer of a Cu-water nanofluid in a differentially heated skewed enclosure. The effect of nanoparticles size, volume fraction, Brownian diffusion and thermophoretic diffusion on the mixed convection is studied and compared with the result due to the homogeneous model. The theromphysical properties of the nanofluid is considered to depend on the temperature and nanoparticle volume fraction. A pressure correction based algorithm is used to solve the transport equations.The effects of the relevant parameter such as, the size of the nanoparticles (30nm⩽dp⩽100nm), temperature difference (1K⩽ΔT⩽10K) and bulk volume fraction of the nanoparticles (0⩽ϕb⩽0.05) on mixed convection of nanofluid studied by considering the skew angle to vary between 30° and 150°. The analysis shows that the nanoparticles distribution is nonuniform inside the enclosure and this non-uniformity increases with the rise of the temperature difference. The variation of the average Nusselt number and total entropy generation with the variation of the relevant parameter is analyzed for the thermodynamic optimization. The purpose of the present study is to analyze the effects of Brownian diffusion and thermophoresis of nanoparticles on the mixed convection of a Cu-water nanofluid. The results show that the Brownian diffusion and thermophoretic diffusion has relatively negligible effects on the mixed convection for the considered range of parameter values.
•Mg composites containing nano-ZnO particulates have been successfully synthesized.•Mg/ZnO nanocomposites exhibit superior mechanical response compared to pure Mg.•Addition of nano-ZnO to Mg resulted ...in grain refinement and texture weakening.
In this study, the effects of nanoscale ZnO reinforcement on the room temperature tensile and compressive response of monolithic Mg were studied. Experimental observations indicated strength properties improvement due to nanoscale ZnO addition. A maximum increment in tensile yield strength by ∼55% and compressive yield strength by 90% (with reduced tension–compression asymmetry) was achieved when 0.8vol.% ZnO nanoparticles were added to Mg. While the fracture strain values under tensile loads were found to increase significantly (by ∼95%, in case of Mg–0.48ZnO), it remained largely unaffected under compressive loads. The microstructural characteristics studied in order to comprehend the mechanical response showed significant grain refinement due to grain boundary pinning effect of nano-ZnO particles which resulted in strengthening of Mg. Texture analysis using X-ray and EBSD methods indicated weakening of basal fibre texture in Mg/ZnO nanocomposites which contributed towards the reduction in tension–compression yield asymmetry and enhancement in tensile ductility when compared to pure Mg.
Abstract
Water pollution presents a significant global challenge that impacts the environment. The release of industrial effluents significantly contributes to this. Adsorption studies offer a ...sustainable and cost‐effective solution to efficiently remove organic pollutants from water. The current study comprises a polypyrrole/nickel molybdate composite for the effective adsorption of organic dyes, such as methylene blue, from aqueous solutions. The catalyst has been comprehensively characterized using various techniques, including XRD, FE‐SEM, FT‐IR, HR‐TEM, XPS, BET, TGA, zeta potential, and DLS analysis. Adsorption studies demonstrate up to 97% removal efficiency in 60 min. This study also evaluates the impact of various parameters, such as temperature, pH, dye concentration, and quantity of the catalyst, on the adsorption efficiency. The
R
2
value of 0.99 that is obtained in the kinetics study suggests the suitability of the adsorption process toward pseudo‐second‐order kinetics. The adsorption isotherm study reveals that the adsorption follows Freundlich's adsorption isotherm. The maximum adsorption capacity of the study is found to be 17.76 mg/g. Investigations into thermodynamic study give a ∆H value of −19.21 J/mol K, indicating the exothermic behavior, and ∆G of −6.95 KJ/mol, suggesting the spontaneity of the composite during the adsorption process. These results demonstrate the potential of the developed material as an effective adsorbent for removing organic dyes from water sources.
Given the increasing scarcity of production resources such as water, energy and labour coupled with growing climatic risks, maize-based production systems could be potential alternatives to intensive ...rice-wheat (RW) rotation in western Indo-Gangetic Plains (IGP). Conservation agriculture (CA) in maize systems has been widely promoted for minimizing soil degradation and ensuring sustainability under emerging climate change scenario. Such practices are also believed to provide mitigation co–benefits through reduced GHG emission and increased soil carbon sequestration. However, the combined effects of diversified crop rotations and CA-based management on GHG mitigation potential and other co-benefits are generally over looked and hence warrant greater attention. A field trial was conducted for 5–years to assess the changes in soil organic carbon fractions, mineral–N, N2O emission and global warming potential (GWP) of maize-based production systems under different tillage & crop establishment methods. Four diversified cropping systems i.e. maize–wheat–mungbean (MWMb), maize–chickpea–Sesbania (MCS), maize–mustard–mungbean (MMuMb) and maize–maize–Sesbania (MMS) were factorially combined with three tillage & crop establishment methods i.e. zero tilled permanent beds (PB), zero–tillage flat (ZT) and conventional tillage (CT) in a split–plot design. After 5–years of continued experimentation, we recorded that across the soil depths, SOC content, its pools and mineral-N fractions were greatly affected by tillage & crop establishment methods and cropping systems. ZT and PB increased SOC stock (0–30 cm depth) by 7.22–7.23 Mg C ha−1 whereas CT system increased it only by 0.88 Mg C ha−1as compared to initial value. Several researchers reported that SOC & mineral–N fraction contents in the top 30 cm soil depth are correlated with N2O–N emission. In our study, global warming potential (GWP) under CT system was higher by 18.1 and 17.4%, compared to CA-based ZT and PB, respectively. Among various maize systems, GWP of MMS were higher by 11.2, 6.7 and 6.6%, compared that of MWMb (1212 kg CO2–eq. ha−1), MCS (1274 kg CO2–eq. ha−1) and MMuMb (1275 kg CO2–eq. ha−1), respectively. The results of our study suggest that CA and diversified crop rotations should be promoted in north-western IGP and other similar agro-ecologies across the globe for ensuring food security, restoration of soil health and climate change mitigation, the key sustainable development goals (SDGs).
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•Soil C fractions and N dynamics and N2O emissions from different tillage and diversified cropping systems were analysed.•The mass equivalent SOC stock and mineral-N fractions increased dramatically in CA practices.•Greater N2O fluxes occurred in CT than CA based systems.•The higher SOC and mineral-N, with lower N2O fluxes were found in MWMb and MCS than in MMS cropping system.
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