Current-Density Functional Theory of the Response of Solids

The response of an extended periodic system to a homogeneous field (of wave-vector $q=0$) cannot be obtained from a $q=0$ time-dependent density functional theory (TDDFT) calculation, because the Runge-Gross theorem does not apply. Time-dependent {\em current}-density functional theory is needed and demonstrates that one key ingredient missing from TDDFT is the macroscopic current. In the low-frequency limit, in certain cases, density polarization functional theory is recovered and a formally exact expression for the polarization functional is given.Comment: 5 pages, accepted in PR

Magnetic, orbital and charge ordering in the electron-doped manganites

The three dimensional perovskite manganites in the range of hole-doping $x > 0.5$ are studied in detail using a double exchange model with degenerate $e_g$ orbitals including intra- and inter-orbital correlations and near-neighbour Coulomb repulsion. We show that such a model captures the observed phase diagram and orbital-ordering in the intermediate to large band-width regime. It is argued that the Jahn-Teller effect, considered to be crucial for the region $x<0.5$, does not play a major role in this region, particularly for systems with moderate to large band-width. The anisotropic hopping across the degenerate $e_g$ orbitals are crucial in understanding the ground state phases of this region, an observation emphasized earlier by Brink and Khomskii. Based on calculations using a realistic limit of finite Hund's coupling, we show that the inclusion of interactions stabilizes th e C-phase, the antiferromagnetic metallic A-phase moves closer to $x=0.5$ while th e ferromagnetic phase shrinks in agreement with recent observations. The charge ordering close to $x=0.5$ and the effect of reduction of band-width are also outlined. The effect of disorder and the possibility of inhomogeneous mixture of competing states have been discussed.Comment: 42 pages, 16 figure

A new insight towards eggshell membrane as high energy conversion efficient bio-piezoelectric energy harvester

Bio-inspired piezoelectric materials have been considered as excellent energy harvesting source for their non-toxic and biocompatibility nature which have ability to generate and supply significant power to the energy deficient world without any environmental pollution. Till date, fabrication of bio-piezoelectric nanogenerator (BPNG) with high power density and high energy conversion efficiency is of great concern. Here, we have explored the potentiality of an inexpensive and bio-waste porous eggshell membrane (ESM) as an efficient piezoelectric material with piezoelectric strength of ≈23.7 pC/N. The fabricated bio-nanogenerator (ESMBPNG) provides high output voltage (≈26.4 V), current (≈1.45 μA) and high energy conversion efficiency of ≈63% with maximum instantaneous power density (≈238.17 μW/cm3) under mechanical stress of ≈81.6 kPa. Assembling five ESMBPNGs provides an output voltage of ≈131 V that lights-up more than 90 green LEDs and produced ≈6 μA current in series and parallel connections, respectively, suggesting its effectiveness towards commercialization. Moreover, ESMBPNG is ultrasensitive towards very minute pressure arising from pulse, body motions at rest and walking conditions, water drop, and writing on the device as well. This work would have a significant role towards up-lifting the green energy harvesting technology as self-powered implantable and wearable electronics. © 2018 Elsevier Ltd11Nsciescopu

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Not AvailableMicrobial mobilization of sediment calcium-bound P constitutes an important process of P cycling in aquatic environments. The present study was conducted to identify the bacterial community responsible for inorganic phosphate solubilization in tropical oxbow lakes. Fifty eight phosphate-solubilizing bacteria were isolated from bottom soil, water, and fish gut and examined for solubilization of tricalcium phosphate. Results revealed aquatic PSB to be low-to-moderately capable in P solubilization (mean: 33.5 mg P L−1; range: 6.3–68.8 mg P L−1), and bacteria from wetland sediment and water were more effective than those from fish gut. The PSB were identified to belong to diverse genera, viz. Bacillus, Brevibacillus, Enterobacter, Agrobacterium, Pseudomonas, Acinetobacter, Microbacterium, Curtobacterium, Stenotrophomonas and Novosphingobium. The findings help in understanding the microbial role in inorganic P solubilization and identifying important P solubilizers in freshwater environments.Not Availabl

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Not AvailablePhosphorus (P) is a limiting nutrient determining the trophic state in freshwater ecosystems. Besides Fe-P interaction, organic matter decomposition is important in sediment P chemistry or release. Although Ca-P often forms the major inorganic P pool in sediment, role of Ca-P in P cycling! release is not well studied. The present work conducted in laboratory microcosm using freshly collected floodplain wetland sediment showed that lower pH and moderate to high temperature slowly and significantly influence the Ca-P release; redox condition has less defined role. Besides Ca-P dissolution and P release by microbiota, including phosphate solubilizing bacteria, temperature also dictates microbial P requirement and uptake, ultimately determining the available P level in sediment. In winter chemical interactions might majoriy regulate the sedimentary P cycle, however, microbial activities play an important role in P mobilization during summer.Not Availabl

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Not AvailableA field experiment with sunnhemp (Crotalaria juncea L.) -wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system was conducted during 2004 and 2005 to study the effect of phosphorus and farmyard manure levels on yield and nutrient uptake of sunnhemp and their residual effect on wheat and changes in soil fertility status. Application of farmyard manure @ 5 tonnes/ha recorded an increase of 13.9% in fibre yield over the no farmyard manure. Fertilizer phosphorus significantly increased the fibre yield of sunnhemp by 14.69% over the no phosphorus at 40 kg P2O5/ha. The highest fibre yield (0.90 tonne/ha) was recorded with combined application of 60 kg P 2O5 and 7.5 tonnes farmyard manure/ ha which was 45.2% higher than the yield of without phosphorus and farmyard manure. The total nitrogen, phosphorus and potassium uptake by sunnhemp increased significantly with applied phosphorus up to the maximum level of 60 kg P2O 5/ha but the favourable effect with farmyard manure was recorded up to 5 tonnes/ha only. The increase in nitrogen, phosphorus and potassium uptake with 60 kg P2O5/ha were 20.5, 44.0 and 54.9% respectively over no phosphorus. Grain and straw yield of wheat increased significantly with farmyard manure at 5 and 7.5 tonnes/ha applied in sunnhemp over no farmyard manure although the yield recorded with 5 and 7.5 tonnes farmyard manure/ ha were at par. The increase in grain and straw yield under 5 tonnes farmyard manure/ha was 6.60 and 14.05% respectively. Combined dose of 60 kg P 2O5 with 7.5 tonnes farmyard manure/ha applied in sunnhemp recorded highest grain yield of wheat (4.55 tonnes/ha) which was 21.3% higher than that of without phosphorus and farmyard manure. The nitrogen, phosphorus and potassium uptake by wheat crop increased significantly due to the residual effect of farmyard manure and phosphorus applied in sunnhemp crop. Application of phosphorus and farmyard manure had significantly improved the organic carbon and available nitrogen, phosphorus and potassium status in post-harvest soil after 2 years of cropping.Not Availabl

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Not AvailableBacillus sp. strain CPSM8 is an efficient solubilizer and mineralizer of phosphorus. Here, we present the 4.39 - Mb draft genome sequence of the strain, providing insight into the phosphorus-releasing genes related to productivity in aquatic habitats.Not Availabl