The complexity of the Indian summer monsoon precipitation makes it’s prediction a challenging task as it is not only influenced by the large-scale flows but also by the micro-scale features. In a ...dynamical model, precipitation is resulted from the formation of clouds. The cloud formation and its processes occur at a micro scale. Current state-of-the-art dynamical models lack proper representation of the cloud processes, particularly at high resolutions for which the cloud processes are parameterized, thereby poorly resolving the precipitation. This study aims at examining the impact of the cloud parameters on the simulation of Indian summer monsoon precipitation in Regional Climate Model version 4 (RegCM4). The autoconversion coefficient which determines the conversion of cloud water into precipitation in the Explicit Moisture Convergence scheme is adjusted in the RegCM4. The impact of autoconversion is experimented with ten different values and it is found that it has a significant effect on the simulation of precipitation during summer monsoon season. The experiments are conducted by changing autoconversion from 1.5 × 10
−4
to 7.5 × 10
−4
/s along with the default value of 2.5 × 10
−4
/s. On changing the autoconversion values from 60 to 300% of the default value, the precipitation pattern improves over most parts of India. The model simulates the rainfall better when the autoconversion coefficient is changed to 7.5 × 10
−4
/s. With the best outcome with the adjusted autoconversion and control configuration, the model is simulated for seventeen monsoon seasons and the analyses of RegCM4 simulated vertically integrated moisture transport, convective available potential energy and atmospheric moisture budget suggest that the model efficacy is enhanced in higher autoconversion value than the control one. Statistical evaluations using bias, correlation coefficients, comprehensive rating matrices and skill score confirm the suitability of higher autoconversion rate for summer monsoon simulations. The model with adjusted autoconversion coefficient (at 7.5 × 10
−4
/s) has improved the representation of seasonal precipitation distribution and its year-to-year variation including other derived features. The rainfall pattern is improved over North West India and North East India especially, the monsoon core regions. The mean seasonal rainfall is in phase 94% of the time with the modeler-adjusted moisture as compared to 82% in the control in the long term simulation.
We examine the dynamics of emerging market (EM) local currency government bond yields for the last decade and a half as well as for three different phases (January 2000–December 2007, January ...2008–April 2013, and since May 2013). We show that domestic factors have anchored EM local currency government bond yields, increasing the potential diversification benefit. Moreover, these yields have become relatively resilient to global risk aversion shocks. Yet, EM local currency government bond yields have been affected partly by very low US Treasury yields and are susceptible to the latter's increases.
Wound dressings that can be formed in situ offer several advantages over the use of preformed dressings such as conformability without wrinkling or fluting in the wound bed, ease of application and ...improved patient compliance and comfort. Here we describe such an in situ forming hydrogel wound dressing from gelatin, oxidized alginate and borax. Periodate oxidized alginate rapidly cross-links proteins such as gelatin in the presence of borax to give in situ forming hydrogels that are both non-toxic and biodegradable. The composite matrix has the haemostatic effect of gelatin, the wound healing-promoting feature of alginate and the antiseptic property of borax to make it a potential wound dressing material. The hydrogel was found to have a fluid uptake of 90% of its weight which would prevent the wound bed from accumulation of exudates. The water vapour transmission rate (WVTR) of the hydrogel was found to be 2686±124
g/m
2/day indicating that the hydrogel can maintain a moist environment over wound bed in moderate to heavily exuding wound which would enhance epithelial cell migration during the healing process. The wound healing efficacy of hydrogel was evaluated in experimental full thickness wounds using a rat model which demonstrated that within 2 weeks, the wound covered with gel was completely filled with new epithelium without any significant adverse reactions. These in situ forming hydrogels fulfil many critical elements desirable in a wound dressing material.
Existing flood modeling studies over coastal catchments involving different combinations of model chain setup imparting complex information fails to entail the needs of policy or decision-makers. ...Thus, a comprehensive framework that pertains to the requirements of practitioners and provides more perspicuous flood hazard information is required. In this paper, a novel approach translating complex flood hazard information in the form of decision priority maps derived using a rational combination of models (physical and statistical) is elucidated at the finest administrative scale. The proposed methodology is illustrated over a highly flood-prone deltaic region in Mahanadi River Basin, India, to characterize impacts of climate change for a 1:100 years return period flood event under future conditions (2026–2055). The modeled flood events are further analyzed to capture the transformation dynamics of flood hazard classes (FHCs) in near-future, for prioritizing areas with greater hazard potential. Interestingly, the results capture a high transformation characteristic from low to high FHCs in agriculture-dominated areas, which are significantly greater than the areas experiencing flood hazard reduction. The results show a significant increase of 12.5% and 27.35% in areas with high FHCs under RCP4.5 and RCP8.5 scenarios, respectively. Moreover, a notable climate change response is indicated under both climate change scenarios, with approximately 22% (RCP4.5) and 25% (RCP8.5) in villages showing a drastic increment in flood hazard magnitude. The results thus highlight the importance of identifying and prioritizing the areas for flood adaptation where a relative change in flood hazard potential is higher due to climate change. Therefore, we conclude that this study can provide an insight into the implication of new approaches for effective communication of flood information by bridging the gaps between scientific communities and decision-makers in appraisal for better flood adaptation measures.
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•Model chain setup involved for quantification of hydro-meteorological information.•Top-down approach is used to understand basin's response to climate change.•Signature changes in flood hazard are observed over agriculture-dominated villages.•Transformation of hazard classes is illustrated at the finest administrative scale.•Novel concept of decision priority mapping introduced for effective decision making.
With the increasing trend in the use of light-weight functional material in emerging industrial applications, understanding the fabrication of aluminum–boron carbide (ABC) composite is becoming ...needful. In this context ABC composites up to 25
wt.% boron carbide (B
4C) particulate reinforcement in alumnium 1100 matrix were prepared at 873
K and the resulting microstructure and physico-mechanical properties were studied. Dark-field images showed the continued existence of porosities. The density and electrical conductivity decreased from 2.52% to 1.8% and from 48% to 11% of the International Annealed Copper Standard, respectively. There was an 11-fold increase in hardness with 25
wt.% B
4C addition. Although the flexure strength of the composite decreased because of transition in formation of phases at grain boundaries from ternary Al–B–C to binary Al–B, growth of Al–B and retention of boron carbides, the flexure modulus showed up to 8 times improvement with increased fraction of reinforcement. Fractographs revealed extensive damage to grain boundaries because of generated shear and particle pull-out. The tendency for brittle fracture increased with higher reinforcement fractions. The study forms the basis to commercialise ABC composites for required applications, and it is concluded that even though uncoated boroncarbide reinforcements embrittle the aluminum matrix in as-reinforced condition, improvement in other as discussed properties is significant. The study also indicates that the ductility of the metal matrix composite (MMC) may be improved by increasing the interfacial bonding and decreasing the overall porosity contents of the composite.
The impact of soil moisture (SM) in the regional climate model RegCM4.6 is investigated for the simulation of Indian summer monsoon seasonal rainfall and its spatiotemporal variability. For this ...purpose, the model is initialized with soil moisture from five different sources such as the (1) European Space Agency Climate Change Initiative (ESACCI), (2) Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), (3) Climate Prediction Center (CPC), (4) ECMWF's reanalysis (ERA) of the twentieth century (ERA-20C), and (5) corrected ERA (CERA). There is a notable discrepancy in the magnitude and distribution of SM among the different sources. In the first stage of the experiment, the model is integrated for two deficit (1982 and 1987), two excess (1983 and 1988), and two normal (1984 and 1989) monsoon seasons to identify the best suitable SM source. Soil moisture tends to have a positive relationship with precipitation and evapotranspiration and a negative relation with sensible heat flux. The CPC SM having a correlation coefficient of 0.6 performs better than the other sources, and it is hence used for long-term simulations of the recent 18 monsoon seasons. We suggest that the initialization of RegCM using CPC data is suitable since the model skill is higher than the other sources of SM. Comprehensive statistical analyses also confirm that the CPC is a better choice over the other sources, and the skill of the model, while using CPC improves over the control experiment. The performance index is higher with the CPC data than the control experiment for a longer-period simulations. The number of phase-synchronizing events based on the standardized anomaly index suggest that the CPC anomaly is aligned in the same direction to the observed rainfall anomaly in 13 of the 18 seasons, whereas the control experiment is aligned for nine of the 18 monsoon seasons. Also, the skill of the model increases from 0.48 with the control experiment to 0.56 with the CPC-initialized experiment.
Summary
Worldwide, conservation agriculture practices involving minimal soil disturbances and retention of crop residue (>30%) have been practised increasingly and recognized to enhance soil health ...by optimizing key soil attributes. However, little information is available on the short‐term effects of conservation agriculture practices on soil properties under rainfed Vertisols of Central India. Thus, our aim was to study the short‐term effects of contrasting tillage treatments and cropping systems on soil aggregation, aggregate‐associated carbon (C), carbon pools and crop productivity. This study comprised three tillage systems (TS), reduced tillage (RT), no tillage (NT) with retention of crop residue and conventional tillage (CT), together with four cropping systems (CS), namely soya bean (Glycine max L.) + pigeon pea (Cajanus cajan L.) (2:1), soya bean–wheat (Titricum durum L.), maize (Zea mays L.) + pigeon pea (1:1), and maize–chickpea Cicer arietinum L.). The experiment was laid out in a split‐plot design with three replicates. Soil samples were collected at four depths: 0–5, 5–15, 15–30 and 30–45 cm from the experimental field after completion of four crop cycles. Results indicated that at depths 0–5 and 5–15 cm, tillage and cropping system had a significant effect on aggregate mean weight diameter (MWD). The MWDs of 0.97 and 0.94 mm were larger for NT than CT (0.77 and 0.83 mm) at 0–5‐ and 5–15‐cm depths, respectively. Water‐stable aggregates (WSAs) were also larger for NT (70.74%) and RT (70.09%) than CT (59.50%) at 0–5 cm. Tillage practice, cropping system and their interaction had a greater effect (P < 0.05) on the content of aggregate‐associated C for large macroaggregates (LM). There was more aggregate‐associated C for NT and RT at 0–5‐cm depth than for CT. Cropping system also had a significant effect (P < 0.05) on aggregate‐associated C at 0–5‐cm depth. Soil organic C (%) fractions were in the order of non‐labile >very labile >less labile >labile for 0–5‐ and 5–15‐cm depths after four crop cycles. Less labile and non‐labile C fractions contributed >50% of TOC, indicating a more recalcitrant form of carbon present in the soil. Tillage had no significant effect (P > 0.05) on crop yields after four crop cycles. Conservation agriculture can have a positive effect on aggregate stability, aggregate‐associated C and different carbon pools in a Vertisol.
Highlights
Does conservation agriculture affect soil aggregation, aggregate stability and carbon pools more than conventional tillage?
The SOC concentration increases with aggregate size and provides physical protection and stabilization of carbon (C).
Aggregate‐associated C content was significantly affected by tillage practices and cropping system.
Less labile and non‐labile C fractions contribute >50% TOC in the rainfed Vertisols of central India.
Of late, intensive farming for higher food production is often associated with many negative implications for soil systems, such as decline of soil organic matter (SOM), increase in risks of soil ...erosion by wind and/or water, decline in soil biological diversity, increase in degradation of soil physical quality, lower nutrient-use efficiency, high risks of groundwater pollution, falling water tables, increasing salinization and waterlogging, in-field burning of crop residues, pollution of air and emission of greenhouse gases (GHG), leading to global warming, and decline in factor productivity. These negative implications necessitate an objective review of strategies to develop sustainable management practices, which could not only sustain soil health and ensure food security, but also enhance carbon sequestration, decrease GHG emissions, and offer clean and better ecosystem services. Conservation agriculture (CA), that includes reduced or no-till practices along with crop residue retention and mixed crop rotations, offers multiple benefits. Adoption of a system-based CA conserves water, improves and creates more efficient use of natural resources through the integrated management of available soil nutrients, water, and biological resources, and enhances use efficiency of external inputs. Due to apparent benefits of CA, it is increasingly being adopted and now covers about 180 million hectares (Mha) worldwide. However, in South Asia its spread is low (<5 Mha), mostly concentrated in the Indo-Gangetic Plains (IGP). In this region, one of the serious issues is "residue burning" with severe environmental impacts. A huge amount of crop residue left over after the combine harvest of rice has forced farmers to practice widespread residue burning (∼140 M tonnes) to cope with excessive stubble and also for timely planting/sowing of succeeding crops.
In rice-wheat cropping systems, which cover more than 10 Mha in the IGP, CA practices are relatively more accepted by farmers. In these systems, any delay in sowing leads to yield penalty of 1-1.5% per day after the optimum sowing date of wheat. The strong adoption of CA practices in IGP is mainly to overcome delayed sowing due to the field preparation and control of weeds, timely planting, and also escape from terminal heat during the grain-filling stage. Major challenges to CA adoption in South Asia are small land holdings (<1 ha), low technological reach to farmers, nonavailability of suitable farm implements for small farm holders, and the staunch conventional farming mind-set. South Asia region consists of many countries of diverse agro-ecologies with contrasting farming systems and management. This region, recently known for rapid economic growth and increasing population, necessitates higher food production and also hot-spots for adoption of CA technologies. Therefore, in this review critically explores the possibility, extent of area, prospects, challenges, and benefits of CA in South Asia.
HIGHLIGHTS
Conservation agriculture (CA), consisting of reduced or no-tillage and crop residue retention, is a self-sustainable system which offers an alternative to crop residue burning.
The CA approach improves soil health by increasing soil organic carbon (SOC) and aggregation and also conserves soil, water and energy than conventional farming systems.
South Asian countries are suitable for adoption of CA practices but the area under CA remains low (<5 Mha) as compared to the global area (180 Mha).
Adoption of CA in South Asia has skewed distribution, mainly in Indo-Gangetic Plains (IGP) in India, Pakistan, Nepal and Bangladesh in South Asia.
Development of herbicide-resistant weed species and weed shift by continuous application of herbicides are the major challenges in adoption of CA.
The traditional-farming mind-set, socio-economic conditions, small farm-holdings, weed and residue management, and non-availability of suitable machinery are key constraints to the low adoption of CA practices in South Asia.
In this article, detailed investigations on structural, dielectric, impedance, and leakage current characteristics of samarium modified bismuth titanate of chemical formula (Bi3.9Sm0.1Ti3O12), ...prepared by cost-effective solid-state reaction technique (with 850 °C calcination and 900 °C sintering temperatures), have been discussed. The X-ray structural study has shown that the compound crystallizes in orthorhombic symmetry with the B2ab space group. SEM micrograph at room temperature displays the grains are uniformly distributed on the surface with a very small amount of voids. The electrical measurements of the compound were carried out by a phase-sensitive (LCR) meter over broad temperature (25 °C–400 °C) and frequency (1 kHz-1 MHz) ranges. The hysteresis loops between polarization (P) and electric field (E) at different temperatures show the existence of ferro-electricity in the compound. All the electrical characteristics have shown significant modification on even a small substitution (i.e., 10%) of trivalent rare earth element (i.e., samarium) in the bismuth site. The leakage current study at various temperatures shows the existence of Ohmic conduction in the compound. The value of leakage current makes the sample preferable for electronic devices.
•Room temperature XRD analysis determines the orthorhombic structure of the compound with B2ab space group.•The SEM micrograph indicates that the grains are uniformly distributed with a few voids.•A high dielectric constant and low tangent loss makes the material suitable for device application.•The J-E characteristics of the sample indicate the Ohmic conduction along with the absence of the SCLC mechanism.•Ferroelectric behavior of the material is confirmed from the P-E hysteresis loop.
In Vertisols of the semi-arid tropics lack of optimum soil water and low soil temperature (<18
°C) during germination, and high soil temperature (>37
°C) during pod development stage has been a major ...barrier to realizing yield potential of summer groundnut. Seven field experiments (comparing straw with polythene, 50
μm gauge mulch, duration of retention of polythene mulch, testing the combined effect of straw and polythene mulch, N management in straw mulch and field demonstration) were carried out from 1992 to 1999 in a sequence to identify a suitable mulch material, which was socially and economically acceptable and could overcome soil water and soil temperature related problems for summer groundnut. In general, straw mulch (wheat or paddy) produced more pod (17–24%) and haulm yields (16%) of groundnut than polythene mulch (black or transparent) and no mulch because of favourable soil water and soil temperature, earlier seedling emergences, more flower and mature pods numbers, lower bulk density and less weeds. We observed that groundnut plants showed N deficiency under wheat straw mulch at the early stage (up to 60 days after sowing). However, towards maturity N deficiency occurred at the early stage had no significant negative impact on pod yield of groundnut because the plants recovered N deficiency and had greater chlorophyll content and pod yield. This is presumed to be associated with bio-availability of macro and micronutrient during decomposition of organic mulch. The pod yield of groundnut under black polythene was higher than under transparent polythene. The polythene mulch increased soil temperature by 4–5
°C through out the crop growth (germination to maturity), which increased seeding emergence but was detrimental to pod setting and pod development (soil temperature exceeded 40
°C). Thus, the benefit of polythene was only observed when it was retained up to podding stage, but not up to harvest. The combined application of wheat straw and black polythene out-yielded sole application of wheat straw mulch but the former was 45% less profitable than the later one because of the cost of polythene. Wheat straw mulch was finally demonstrated to the farmer's field. It was found that sacrificing 5
t wheat straw as cattle feed, farmers on return get additional 0.47
t
ha
−1 legume fodder due to mulching which is nutritionally superior quality fodder in terms of crude protein, phosphorus content, crude fiber, ash and silica content compared to wheat straw as cattle feed. Thus, 16% additional production of highly nutritive groundnut haulm due to mulching has a significant implication on (i) nutritional fodder security, especially during the dry season when green fodder is costly and its availability is limited, and (ii) additional income of Rs. 3935
ha
−1 from mulch. These two considerations, apart from solving temperature related problems convinced 32 farmers of Vadhvi and Zanjarda village of Junagadh district, Gujarat for adoption of wheat straw technology for summer groundnut in about 50
ha areas.
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