Space-charge limited conduction in epitaxial chromia films grown on elemental and oxide-based metallic substrates

We study temperature dependent (200 – 400 K) dielectric current leakage in high-quality, epitaxial chromia films, synthesized on various conductive substrates (Pd, Pt and V2O3). We find that trap-assisted space-charge limited conduction is the dominant source of electrical leakage in the films, and that the density and distribution of charge traps within them is strongly dependent upon the choice of the underlying substrate. Pd-based chromia is found to exhibit leakage consistent with the presence of deep, discrete traps, a characteristic that is related to the known properties of twinning defects in the material. The Pt- and V2O3-based films, in contrast, show behavior typical of insulators with shallow, exponentially-distributed traps. The highest resistivity is obtained for chromia fabricated on V2O3substrates, consistent with a lower total trap density in these films. Our studies suggest that chromia thin films formed on V2O3 substrates are a promising candidate for next-generation spintronics

Genetic diversity, population structure, and genome‑wide association study for the flowering trait in a diverse panel of 428 moth bean (Vigna aconitifolia) accessions using genotyping by sequencing

Background Moth bean (Vigna aconitifolia) is an underutilized, protein-rich legume that is grown in arid and semiarid areas of south Asia and is highly resistant to abiotic stresses such as heat and drought. Despite its economic importance, the crop remains unexplored at the genomic level for genetic diversity and trait mapping studies. To date, there is no report of SNP marker discovery and association mapping of any trait in this crop. Therefore, this study aimed to dissect the genetic diversity, population structure and marker-trait association for the flowering trait in a diversity panel of 428 moth bean accessions using genotyping by sequencing (GBS) approach. Results A total of 9078 high-quality single nucleotide polymorphisms (SNPs) were discovered by genotyping of 428 moth bean accessions. Model-based structure analysis and PCA grouped the moth bean accessions into two subpopulations. Cluster analysis revealed accessions belonging to the Northwestern region of India had higher variability than accessions from the other regions suggesting that this region represents its center of diversity. AMOVA revealed more variations within individuals (74%) and among the individuals (24%) than among the populations (2%). Marker-trait association analysis using seven multi-locus models including mrMLM, FASTmrEMMA FASTmrEMMA, ISIS EM-BLASSO, MLMM, BLINK and FarmCPU revealed 29 potential genomic regions for the trait days to 50% flowering, which were consistently detected in three or more models. Analysis of the allelic effect of the major genomic regions explaining phenotypic variance of more than 10% and those detected in at least 2 environments showed 4 genomic regions with significant phenotypic effect on this trait. Further, we also analyzed genetic relationships among the Vigna species using SNP markers. The genomic localization of moth bean SNPs on genomes of closely related Vigna species demonstrated that maximum numbers of SNPs were getting localized on Vigna mungo. This suggested that the moth bean is most closely related to V. mungo. Conclusion Our study shows that the north-western regions of India represent the center of diversity of the moth bean. Further, the study revealed flowering-related genomic regions/candidate genes which can be potentially exploited in breeding programs to develop early-maturity moth bean varieties

Functionalized multiwalled carbon nanotubes based hydrogen gas sensor

Carbon nanotubes (CNTs) are extremely sensitive to environmental gases. Detection of H-2 gas at room temperature with fast response and recovery time is still a challenge. Here, we report that 0.05% H-2 gas at room temperature can be detected using acids functionalized multiwalled carbon nanotubes (F-MWCNTs). F-MWCNTs showed faster response to H-2 gas as compared to pristine multiwalled carbon nanotubes (P-MWCNTs). The effect of functionalization on the P-MWCNTs structure and their electrical properties are investigated using different techniques. The calculated crystallite size of the acids treated nanotubes from the Raman spectra is found to decrease to 14.6 nm as compared to 15.2 nm for the pristine. Also, due to attchements of functional groups on the nanotubes, the interplanar size of F-MWCNTs is increased, as identified from high resolution transmission electron microscopy (HR-TEM) and the X-ray diffraction (XRD) analysis. The presence of functional groups at the nanotubes walls after acids treatments is confirmed by fourier transform infrared (FTIR) spectra. Furthermore, the current carrying capacity of F-MWCNTs is found to increase to 35 mA from 49 mu A at low sweep voltage. It is also observed that, the recovery time of F-MWCNTs sensor decreases to 100 s for 0.05% of H-2 gas as compared to 190s for the P-MWCNTs. (C) 2013 Elsevier B.V. All rights reserved

Room temperature hydrogen gas sensors of functionalized carbon nanotubes based hybrid nanostructure: Role of Pt sputtered nanoparticles

Fast detection of H-2 gas at room temperature has constantly remained a challenge. The metal-oxide based gas sensors have shown excellent sensing properties for gases like H-2, NO, CO and NH3. In the present work, the H-2 gas sensing characteristics of multiwalled carbon nanotubes based hybrid sensor (F-MWCNTs/TiO2/Pt) has been reported. The fabricated sensor shows 3.9% sensitivity for low concentration i.e. 0.05% of H-2 with good repeatability and stability at room temperature. The sensing response of F-MWCNTs/TiO2/ Pt is interrelated to change in their resistance on the introduction of H-2 gas and this phenomenon is required for deep understanding the effect of H-2 adsorption on their electronic conduction. The improvement in sensitivity of F-MWCNTs/TiO2/Pt as compared to MWCNTs/TiO2 towards H-2 is because of the catalytic role of dispersed Pt nanoparticles deposited by sputtering. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

A RULEBASE PHYSIOGRAPHIC CHARACTERIZATION OF A DROUGHT PRONE WATERSHED APPLYING REMOTE SENSING AND GIS

Efficient micro-watershed management needs characterization of it to optimize natural resources, which is especially important in drought prone areas. In the present study micro-watersheds of Gandheshwari tributary in Chotta-Nagpur Plateau are characterized based on physiographic properties towards agricultural potentiality. An algorithm interpolating elevation values using an empirical formula is proposed to obtain an improved Digital Elevation Model (DEM). IRS LISS-III Satellite data is used to acquire important parameters like landuse/landcover and drainage. Image processing techniques like edge enhancement, edge detection, and principal components analysis are used for improving lineament detection. For characterization of watershed landform analysis using physiographic parameters is done in Geographic Information System (GIS). Detailed drainage network obtained from satellite image, the improved DEM and other GIS layers of land based information are used to delineate micro-watersheds. The Agricultural Hydrologic Response Units (AHRU) targeting agricultural use of the land are derived by overlaying the delineated parameters and are grouped into thirty response units based on their agricultural potential. Micro-watersheds are characterized based on the dominant AHRU giving spatial information about agricultural suitability, emphasizing availability and scarcity of water so that respective water conservation practices can be improved to use the potential AHRU

Not Available

Not AvailableBiophysical models predict the behavior of the land use system in physical terms such as crop yields, environmental effects, and effect on management. Oryza 2000 model Is an eco-physlologlcal crop model to simulate the growth and development of a rice crop in situations of potential production, water limitations, and nitrogen limitations. This paper reports on the calibration and validation of the model using Independent data sets of kharif rice crop. Data are originated from the nitrogen balance experiment conducted by Directorate of Rice Research (DRR), Hyderabad during 2001 .The calibration of the model was performed by deriving the crop growth parameters for DRRHl and Vikas varieties. Results show that there was overestimation of Leaf Area Index (LAl) in all our observations and there was slight overestlmation between simulated and observed weights of the total aboveground dry matter (WAGT and WAGT_OB5) of DRRH1 (13.7%) and Vikas (10.5%) varieties. At maturity date, with respect to grain yield (WRR14) parameter, model has shown slight overestimation with average of observed values of DRRHI (9.5%) and Vlkas (4.3 %). But in each case one of the replications of observed values very nearer to simulated values. Model simulations can be further improved by calibrating other parameters of crop. Hence, calibration to the model at different levels with more intensive field experimental data will Improve the performance of the model and it can be effectively used for different management practices for irrigated rice grown in dry season or wet season.Not Availabl

Not Available

Not AvailableA 2-year (2010–2011) field experiment was conducted under hot arid environment at Bikaner, India to investigate the effects of exogenous sulphydryl (–SH) compounds (thioglycolic acid and thiourea) on the water relation, malondialdehyde (MDA) content, membrane stability, photosynthetic pigment contents, gas exchange parameters and antioxidant enzyme activities in moth bean (Vigna aconitifolia L.) under water limiting environment. Foliar application of –SH compounds significantly reduced MDA content and increased membrane stability, photosynthetic pigment content, gas exchange parameters and antioxidant enzyme activities. The –SH treated plants had 9–14, 10–14, 17–25, 16–74, 14–37% higher relative water content, membrane stability index, total chlorophyll content, antioxidant enzyme activities, and net photosynthetic rate (PN), respectively, whereas the MDA content was 12–21% lower, as compared to non-treated plants. Results suggest that under water limiting situation, exogenous –SH compound application improves photosynthesis, protects plants against oxidative damage by scavenging ROS and minimizing MDA content by elevated antioxidant enzyme activities. Results indicate that exogenous –SH application enhances the activities of antioxidant enzymes and maintains higher photosynthetic rate under water limiting environment and thus helps to improve drought tolerance in moth bean.Not Availabl

Not Available

Not AvailableThis study investigates how spatial technologies like remote sensing and GIS (Geographic Information System) integrated with a crop growth model to estimate paddy rice yields. Two approaches were used to estimate rice yield one is from remote sensing images and another from soil, climate layers of GIS, linked to the crop model. Oryza2000 model was used as a crop model to link with these technologies. Results show that yield estimated from these two approaches were closed to the reported values from department of Agriculture, Andhra Pradesh, India and yield estimated from remote sensing is more precise than GIS layers. This underscores the potential value of remote sensing, GIS and crop model for yield estimation. The successful application of methodology used in our study to other areas will depend on number of factors including the secondary data estimates, distribution of different crops grown in that area, crop condition at the time of satellite overpass and land scene anomalies.Not Availabl