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Composite ionomer membranes with ePTFE reinforcement have been developed to improve operational durability of polymer electrolyte fuel cells by creating a more mechanically robust membrane electrode assembly. The present objective is to determine the morphological damage evolution of a reinforced membrane subjected to pure mechanical degradation by wet/dry cycling in a fuel cell. Identical-location four-dimensional in situ visualization by X-ray computed tomography is used to reveal the progressive degradation stages from initiation via propagation to failure. The observed degradation process is dominated by fatigue driven membrane fracture which is primarily confined under the channel area. When compared to degradation of non-reinforced membranes, the results for the reinforced membrane demonstrate similar non-linear progression of membrane fracture, but at 2-3x lower rate due to the improved fracture resistance of ePTFE reinforcement. Membrane-catalyst layer delamination and catalyst layer cracks are identified as preceding drivers of local membrane fracture, while wet and dry phase in situ imaging demonstrates hydration induced through-plane swelling of 30% and widespread crack closure at advanced degradation states. Overall, these results provide new understanding of mechanical degradation in composite membranes and prospective directions for further durability enhancements. Image 1 • 4D in situ XCT is adopted to track mechanical degradation of reinforced membranes. • The in situ process of fatigue crack propagation is revealed. • Degradation mechanisms of reinforced and non-reinforced membranes are compared. • Catalyst layer cracks and delamination are identified as key drivers of fracture. [ABSTRACT FROM AUTHOR]

Interactions between catalyst layers and membrane are known to influence the mechanical properties of catalyst coated membrane (CCM) composites used in fuel cells, and can further affect their fatigue-driven mechanical fracture — an important lifetime-limiting failure mode in automotive applications. Here, the fracture propagation phenomenon in CCMs is characterized through a series of ex situ experiments and microstructural investigations conducted across a range of stress, temperature (23-70 °C), and relative humidity (50–90%) conditions relevant to low-temperature polymer electrolyte fuel cells. In comparison to pure membranes, the crack propagation rates are slightly arrested in CCMs through mechanical reinforcement offered by the catalyst layers; however, the membrane layer still controls the overall crack growth trends through its temperature and humidity dependent ductile fracture characterized by confined yielding around the fracture surface. Local interfacial delamination and severe electrode cracking are found to accompany the CCM crack propagation, which aids membrane fracture by loss of local reinforcement. A Paris law based fracture modelling framework, incorporating the elastic-viscoplastic mechanical response of CCMs, is developed to semi-analytically evaluate one-dimensional crack growth rate during cyclic loading, and provides reasonably accurate predictions for the present ex situ problem. Image 1 • Ex situ fatigue crack growth rates are characterized for fuel cell CCM composites. • Ionomer membrane governs the general fracture attributes of the CCM. • Electrode layers' mechanical reinforcement contributes in slowing the crack growth. • Electrode cracking, membrane thinning and delamination accompany CCM crack growth. • CCM crack growth rate is simulated with a Paris law based semi-analytical FEM model. [ABSTRACT FROM AUTHOR]

Cyanobacterial diversity from nine hot water springs of North-Western Himalayas scattered over an area of approximately 20,000 km 2 has been studied using polyphasic approach in relation to important ecological factors. These hot springs have hard water, with variation of temperature from 40 to 90 °C and pH from 6.8–8.0. A total of 625 cyanobacterial isolates were cultured from 150 samples. On the basis of morphology, these isolates were represented by 22 species of 11 genera. A total of 220 cyanobacterial isolates representing morpho-species from each sampling site were subjected to molecular characterization by amplified ribosomal DNA restriction analysis (ARDRA), 16S rRNA gene, rbcL gene and cpcB -IGS- cpcA phycocyanin locus region sequencing for elucidating their identity, diversity and phylogenetic relationships. ARDRA analysis revealed 22 groups of cyanobacterial isolates from selected hot water springs. Sequence analysis of 16S rRNA gene, rbcL gene and cpcB -IGS- cpcA phycocyanin locus region revealed that the identity of the majority of the cyanobacterial species was congruent with the identity based on morphological features. The identity of 3 taxa; Leptolyngbya sp. PUPCCC 112.22, Phormidium sp. PUPCCC 118.2 and Phormidium sp. PUPCCC 118.3, based on both morphological features and molecular markers, did not match with known cyanobacterial species, indicating these as new genera/species. Phylogenetic analyses revealed that taxa from selected hot springs belonging to Stigonematales are monophyletic, whereas Chroococcales and Oscillatoriales are polyphyletic. Canonical correspondence analysis of physico-chemical parameters and cyanobacterial community of each hot water spring revealed that temperature, pH, conductivity, nitrogen, sulphate and phosphate influenced cyanobacterial community structure. Further, our study has revealed that the cyanobacterial community of hot water springs is comprised of endemic as well as globally distributed representatives and is influenced by ecological parameters. The nature of the cyanobacterial community structure depended on the water chemistry rather than geographical location of the spring. [ABSTRACT FROM AUTHOR]

Highlights: [•] Efficacy of different bio-regulators for increasing seed production of Egyptian clover under abiotic stress conditions of South Asia is reported. [ • ] Foliar application of salicylic acid at 50mgL−1 and KNO3 at 2% recorded the maximum seed yield and seed quality (germination and seedling vigor index). [•] Sodium benzoate (100mgL−1 and 150mgL−1) and CaCl2 (0.5% and 1.0%) were least effective in increasing seed yield among the different bio-regulators tested. [•] Foliar application of 1% CaCl2 solution produced significantly higher seed yield compared with 0.5% CaCl2. [ABSTRACT FROM AUTHOR]

Abstract: Raised beds are widely used in agriculture in developed countries and have proven to be an excellent option for wheat. Permanent raised beds may also offer benefits for rice–wheat (RW) systems in South Asia, in terms of both production and the possibility that furrow-irrigation may be more efficient than flood irrigation. The performance of a RW system on permanent raised beds (37cm wide, 15cm high, furrow width 30cm) was compared with conventional cultivation on the flat on sandy loam and loam soils in replicated experiments in central Punjab, India. The experiments commenced with wheat sown in November 2002, and were continued for 8 crops. Yields of conventionally tilled wheat (CTW) ranged from 3.6 to 4.9tha−1 and tended to be higher on the loam than on the sandy loam. Yields of wheat on fresh and permanent beds (WB and DDWB, respectively) were similar to yields on CTW and direct-drilled wheat on the flat (DDW) except when establishment was sub-optimal on the beds on both soils in 2004–2005. It was also lower on the beds on the sandy loam in 2002–2003 when tillering did not compensate for the lower sowing rate on the beds. In each case, the poorer performance on beds appeared to be associated with the more rapid drying of the beds than the flats, and thus the need for greater precision in irrigation and sowing management with beds on sandy loam and loam soils. Yield on beds relative to flats did not change as the beds aged. Yields of transplanted rice on permanent beds (TRB) were depressed relative to yields of puddled transplanted rice (PTR) with the same alternate wetting and drying water management, regardless of age of the bed (from 1st to 8th crop) and soil type. Yields of TRB relative to PTR declined as the beds aged, over the first 2–3 years, from about 80 to 90% to less than 50% of PTR. Biomass production in TRB was always significantly less than in PTR, starting from 35d after transplanting. Performance of direct-seeded rice on beds (DSRB) was even poorer. Serious root knot nematode infestation was also a serious problem in transplanted rice on the sandy loam in the absence of continuous flooding, on both TRB and PTR. The DSRB suffered from severe iron deficiency each year on both soils despite several iron sprays beginning as early as 15 days after transplanting, and yields declined from about 60% of PTR with the same irrigation scheduling in the first rice crop to less than 25% of PTR in the third rice crop. Total annual system productivity was highest using puddled transplanted rice (PTR) in rotation with fresh beds (WB) for wheat, CTW or DDW on the flat. Average productivity of these systems over the first 4 years was 9.5tha−1 y−1 on a sandy loam soil and 10.3tha−1 y−1 on a loam soil. Productivity of RW on permanent raised beds with transplanted rice declined as the beds aged, and averaged 77–79% of the productivity of the best systems mainly due to declining yield of TRB relative to PTR. Averaged over the first 3 years, productivity of permanent beds with direct-seeded rice (DSRB) was even lower (only 62–68% of the best systems) due to much lower yields of DSRB. Permanent bed RW systems seem to have limited potential under the prevailing soil and climatic conditions of Punjab, India, with current varieties and management. Further research on permanent raised beds for RW systems should focus on the selection of suitable rice and wheat cultivars, soil health issues such as nematodes and iron deficiency, weed control, irrigation scheduling, N management and soil compaction. [Copyright &y& Elsevier]

Highlights • Sub-surface drip fertigation (SSDF) layered with conservation agriculture in rice-wheat rotation were studied. • Similar or higher grain yields, 40–50% irrigation water saving under SSDF compared to flood irrigated rice- wheat system. • Rice and wheat under SSDF needs 20% less N fertiliser to that under flood irrigation. • Higher net returns from SSDF system with laterals spaced at 67.5 cm compared to flood irrigated rice-wheat system. Abstract The future of the South Asia's rice-wheat (RW) production system is at stake due to continuously depleting aquifers and increasing pressure on underground water under projected climate change scenario. Conventional management factors such as flood irrigation, intensive tillage and residue burning are threatening sustainability of RW system. With increasing adoption of conservation agriculture (CA), sub-surface drip fertigation (SSDF) provides an exceptional opportunity for complementing irrigation water saving benefits. Presently, there is no research evidence on optimum spacing and depth for drip laterals in a CA (direct drilling and residue mulch) based RW system around the globe. This study was therefore, planned to evaluate effects of residue mulch, different spacing and depths of laterals for SSDF on crop yield, irrigation water productivity (WPi), nitrogen use efficiency (NUE) and net returns for CA based RW system in a silt loam soil in northwestern India. Drip laterals were spaced either at 33.75 cm or 67.5 cm, and installation depths were 0, 15 or 20 cm beneath the soil surface and compared with conventional and zero tillage based flood-irrigated RW systems. Grain yield and irrigation water input in rice and wheat were generally similar under different SSDF treatments. Irrigation water savings were 48–53% in rice and 42–53% in wheat under combination of SSDF and CA compared to flood irrigation system. A similar trend in WPi was recorded in both the crops. Residue mulch contributed to higher irrigation water savings, wheat yield and WPi compared to no mulch. Both rice and wheat needed 20% less N fertilizer under SSDF system to obtain grain yields similar to that under flood irrigated crops. Net returns from SSDF system with 67.5 cm lateral spacing were significantly higher compared to flood irrigation system. In conclusion, SSDF system having laterals spaced at 67.5 cm and installed at 15 cm depth provides tangible benefits for substantial saving in irrigation water and energy and increasing NUE and net income for CA based RW system in South Asia. [ABSTRACT FROM AUTHOR]

In the extensive rice–wheat system of north-west (NW) India, harvesting is by large combines and the rice residues are normally burnt after harvest, followed by irrigation and intensive tillage prior to sowing wheat. While in-field retention of crop residues can play an important role in replenishing soil quality and reducing environmental pollution from stubble burning, until recently, there has been no suitable technology for seeding wheat in rice residues. To address this need, a series of machines (‘Happy Seeders’) was developed over the past 10 years, culminating in the development of version 2 of the 9-row Turbo Happy Seeder (v.2). The 9-row Turbo Happy Seeder(v.2) has a weight of 506 kg and can be operated by a 33.6 kW tractor at a work rate of 0.3 ha h −1 . Numerous on-farm trials show that yield of wheat sown into rice residues with the 9-row Turbo Happy Seeder is similar to or higher than yield with straw burning and conventional tillage prior to sowing, while providing many benefits to the farmer. These include greatly reduced fuel consumption and cost of crop establishment, and the ability to sow as soon as desired after harvest, ensuring the possibility of sowing at the optimum time and reducing the need for irrigation. However, adoption has been low to date, despite a 50% price subsidy. Constraints to adoption include the low window of operation of the machine (25 days per year), the low machine capacity compared with conventional seed drills, the inability to operate in wet straw, and the lack of straw spreaders on combine harvesters. Removal of subsidies for diesel and electricity (for pumping groundwater) and implementation of the policy banning in-field straw burning would help to accelerate adoption of technology for direct drilling wheat into rice residues. [ABSTRACT FROM AUTHOR]

Abstract: Sustainability of the rice–wheat rotation is important to Asia''s food security. Intensive cropping with no return of crop residues and other organic materials results in loss of soil organic matter and is not sustainable. We evaluated effect of eight treatments comprised of various combinations of green manure (GM), wheat straw (WS), rice straw (RS), farmyard manure (FYM) and urea alone (control) on physical and hydraulic properties of soil in a rice–wheat experiment (1988–2001) on a loamy sand in Punjab, India. After rice harvest, organic carbon (OC) content in the FYM (0.51%), WS (0.56%) and WS+RS (0.59%) treatments were significantly greater as compared to control (0.42%). With addition of GM to all these treatments; FYM+GM (0.59%), WS+GM (0.60%), WS+RS+GM (0.64%) and GM (0.47%), organic carbon content further increased significantly. Increased OC content of the soil in turn improved its aggregation status, infiltration rate and decreased the bulk density, dispersion ratio and soil strength correspondingly. After wheat harvest mean effects of these organic treatments continued, but their magnitude decreased. The differences in rice yield were not significant among urea, GM and WS applied alone or in combination. However, FYM+GM+urea produced highest yield. There was no residual effect of the long-term application of GM, WS and RS incorporation in wheat yields, but FYM application to rice showed significant residual effects on wheat. [Copyright &y& Elsevier]

Background: The occurrence of stent thrombosis (ST) in real world scenario is far different from that mentioned in the literature. Our study identifies the various parameters of ST.Methods: This is a prospective observational-cohort study where-in consecutive patients who received successful percutaneous transluminal angioplasty (PTCA) over the study period of 1-year was included and were followed for 1-year from the primary procedure.Results: The overall incidence of definite ST was 1.4% and 1.7% at 30 days and 1 year respectively. The most common mode of presentation of ST was ST-elevation myocardial infarction (82.6%). The history of prior PTCA, multi-vessel disease, emergent PTCA, acute coronary syndrome and type B2/C lesions were found to be the independent predictors for definite ST. The incidence of late ST was significantly higher with bare metal stent (BMS) than drug-eluting stent (DES) (OR-2.4, 95% CI:1.3-4.5). At mean follow-up of 13.9 months after ST, the overall mortality was 36.9%. The independent predictors of mortality after ST were post-PTCA thrombolysis in myocardial infarction (TIMI) flow grade < 3, and cardiogenic shock at the time of presentation.Conclusion: The overall incidence of definite ST is high in the real world scenario and the DES fared better than BMS. ST carries a bad prognosis especially so if the patients present in cardiogenic shock, or unable to achieve TIMI-3 flow after PTCA. [ABSTRACT FROM AUTHOR]

The rice–wheat cropping system, occupying 24 million hectares of the productive area in South Asia and China, is important for food security. Monitoring long-term changes in crop yields and identifying the factors associated with such changes are essential to maintain and/or improve crop productivity. Long-term experiments (LTE) provide these opportunities. We analyzed 33 rice–wheat LTE in the Indo-Gangetic Plains (IGP) of South Asia, non-IGP in India, and China to investigate the extent of yield stagnation or decline and identify possible causes of yield decline. In treatments where recommended rates of N, P and K were applied, yields of rice and wheat stagnated in 72 and 85% of the LTE, respectively, while 22 and 6% of the LTE showed a significant (P<0.05) declining trend for rice and wheat yields, respectively. In the rice–wheat system, particularly in the IGP, rice yields are declining more rapidly than wheat. The causes of yield decline are mostly location-specific but depletion of soil K seems to be a general cause. In over 90% of the LTE, the fertilizer K rates used were not sufficient to sustain a neutral K input–output balance. Depletion of soil C, N and Zn and reduced availability of P, delays in planting, decreases in solar radiation and increases in minimum temperatures are the other potential causes of yield decline. A more efficient, integrated strategy with detailed data collection is required to identify the specific causes of yield decline. Constant monitoring of LTEs and analysis of the data using improved statistical and simulation tools should be done to unravel the cause–effect relationships of productivity and sustainability of rice–wheat systems. [Copyright &y& Elsevier]

Rice and wheat are the two most important cereals in the Indo-Gangetic Plains (IGP) and are responsible for the food security of the region. To understand the productivity trends in the transects of the IGP: (1) the climatic potential yields of rice and wheat were simulated using a crop simulation modeling approach and (2) the long-term trends of potential and on-farm yields were compared. The potential yields of rice and wheat in the IGP ranged from 7.7 to 10.7 and 5.2 to 7.9 Mg ha−1, respectively. The upper transects of the IGP are more productive and yield decreases by 27% for rice and by 32% for wheat from transect 2 to transect 5. The rate of change in the potential yield trend of rice from 1985 to 2000 ranged from −0.12 to 0.05 Mg ha−1 per year. Negative yield trends were observed at six of the nine sites, four of which were statistically significant (P<0.05). The decrease in radiation and increase in minimum temperature were the reasons for the yield decline. The potential yield trend of wheat, however, appeared to be stable. On-farm yields of rice also showed a negative trend but for wheat the trend was mostly positive. The adverse changes in the weather parameters and declining trends of potential and on-farm yields of rice should be taken as an indication of a future problem. Regular on-farm monitoring of crops and climatic factors is urgently needed for predicting problems and allowing measures to be taken to improve productivity. [Copyright &y& Elsevier]

• Fatigue cracking in Nafion is predicted using plastically dissipated energy (PDE). • A single experimental data point calibrates the numerical model that calculates the PDE. • Model predictions show a good agreement with the experimental crack growth rates. • Crack growth criterion (Critical-PDE) for Nafion varies with temperature and humidity. • Fatigue characterization using this model significantly reduces the need for testing. Durability of membranes, remains a major obstacle to widespread commercialization of polymer electrolyte membrane fuel cells in the automotive industry. Chemical and mechanical stressors play a role, but the general consensus is that mechanical fatigue, caused by swelling and deswelling of the membrane, is a major contributing factor in its degradation and failure. In order to better understand and predict the fatigue behavior, this study outlines a method to determine the critical plastically dissipated energy (C-PDE) for a typical fuel cell membrane material, Nafion NRE 211. The method employs a numerical simulation of a fatigue test specimen, along with one data point for the Paris-regime fatigue crack growth for that specimen. The results show that the C-PDE, like other properties of Nafion, is a function of both temperature and humidity of the test conditions. The C-PDE decreases with increasing temperature and exhibits a nonmonotonic dependence on humidity. At 50% RH, increasing the temperature from 23 °C to 70 °C results in a drop of the C-PDE for NRE 211 from 3.72 mJ/mm to 1.69 mJ/mm while at 90% RH, the same temperature increase results in a drop of C-PDE from 7.69 mJ/mm to 0.873 mJ/mm. Under a given environmental condition, the C-PDE determined from a single data point, is used to predict the fatigue crack growth for other loads in the Paris-regime and the results are compared to additional experimental data for verification. The numerical and experimental results are in generally good agreement, showing that future characterization of the material using this model, under a wide range of environmental conditions, can be conducted with minimal laboratory testing. [ABSTRACT FROM AUTHOR]