In the present investigation, synthesis, characterizations and the tuning of the optical band gap (
E
g
) of ZnO nanowires (NWs) has been successfully achieved by introducing Mg as an intentional ...impurity with varying concentrations Zn
1
x
Mg
x
O (
x
= 0, 5, 10 and 20 at. %). Although the ionic radius of Mg
2+
(0.57 Å) is close to that of Zn
2+
(0.60 Å) the crystal structure difference and large lattice mismatch between ZnO (wurtzite, 3.25 Å) and MgO (rock salt, 4.22 Å) causes phase segregation in Zn
1
x
Mg
x
O with Mg compositions between 37% <
x
< 62%. Optical measurements of the as grown and Mg doped ZnO NWs shows the optical bandgap tunability from 3.35 eV to 3.65 eV as a function of the Mg content. Rietveld refinement of XRD data for the Mg doped ZnO nanowires confirm the wurtzite structure and a continuous compaction of the lattice (in particular, the
c
-axis parameter) with increasing Mg content. Strong UV with weak visible emission by PL studies establishes the sensitivity of the nanostructures yield, size and band gap to the intentional impurity. This tunability of the band gap of ZnO NWs with an intentional impurity could eventually be useful for optoelectronic applications.
Band-gap tuning and optical investigations of Mg
x
Zn
1
x
O (0
x
20) nanowires synthesized by thermal evaporation of metal zinc powder at 900 °C followed by solid state reaction methods at 500 °C.
The present work was undertaken to study the corrosion behaviour of conducting polymer coating on ferrous material. The synthesis of polyaniline (PAni) powder, its characterization, blending and ...coating formulation are described in details. The yield of synthesized polymer was approximately 90% with a conductivity of 0.20–0.40 S/cm. The coating was formulated by incorporating this PAni powder as pigment. The coating conductivity increased with increase in the solid concentration and saturated in the range of 10–15 wt.%. The results of the corrosion tests on PAni coated steel substrate with 1–50 μm coating thickness exposed to 3.5% NaCl solution were also presented. The corrosion resistance of PAni coated steel was found to be more than 10–15 times higher than the bare steel. Electrochemical impedance spectroscopy study revealed that a continuous charge transfer reaction across the metal–coating interface was responsible for the increase in coating capacitance and decrease in polarization resistance. The potentiodynamic study also showed that the current density significantly decreased in PAni coated steel in comparison to bare steel.
BACKGROUND: Drought is the most severe abiotic stress reducing rice yield in rainfed drought prone ecosystems. Variation in intensity and severity of drought from season to season and place to place ...requires cultivation of rice varieties with different level of drought tolerance in different areas. Multi environment evaluation of breeding lines helps breeder to identify appropriate genotypes for areas prone to similar level of drought stress. From a set of 129 advanced rice (Oryza sativa L.) breeding lines evaluated under rainfed drought-prone situations at three locations in eastern India from 2005 to 2007, a subset of 39 genotypes that were tested for two or more years was selected to develop a drought yield index (DYI) and mean yield index (MYI) based on yield under irrigated, moderate and severe reproductive-stage drought stress to help breeders select appropriate genotypes for different environments. RESULTS: ARB 8 and IR55419-04 recorded the highest drought yield index (DYI) and are identified as the best drought-tolerant lines. The proposed DYI provides a more effective assessment as it is calculated after accounting for a significant genotype x stress-level interaction across environments. For rainfed areas with variable frequency of drought occurrence, Mean yield index (MYI) along with deviation in performance of genotypes from currently cultivated popular varieties in all situations helps to select genotypes with a superior performance across irrigated, moderate and severe reproductive-stage drought situations. IR74371-70-1-1 and DGI 75 are the two genotypes identified to have shown a superior performance over IR64 and MTU1010 under all situations. CONCLUSION: For highly drought-prone areas, a combination of DYI with deviation in performance of genotypes under irrigated situations can enable breeders to select genotypes with no reduction in yield under favorable environments compared with currently cultivated varieties. For rainfed areas with variable frequency of drought stress, use of MYI together with deviation in performance of genotypes under different situations as compared to presently cultivated varieties will help breeders to select genotypes with superior performance under all situations.
ABSTRACT The role of electrostatic electron cyclotron harmonic (ECH) waves in producing diffuse auroral emission O i 1356 on Ganymede is investigated. Electron precipitation flux entering the ...atmosphere of Ganymede due to pitch-angle diffusion by ECH waves into the atmospheric loss-cone is calculated. The analytical yield spectrum approach for electron energy degradation in gases is used for calculating diffuse auroral intensities. It is found that calculated O i 1356 intensity resulting from the precipitation of magnetospheric electrons observed near Ganymede is insufficient to account for the observed diffuse auroral intensity. This is in agreement with estimates made in earlier works. Heating and acceleration of ambient electrons by ECH wave turbulence near the magnetic equator on the field line connecting Ganymede and Jupiter are considered. Two electron distribution functions are used to simulate the heating effect by ECH waves. Use of a Maxwellian distribution with temperature 100 eV can produce about 50-70 Rayleigh O i 1356 intensities, and the kappa distribution with characteristic energy 50 eV also gives rise to intensities with similar magnitude. Numerical experiments are performed to study the effect of ECH wave spectral intensity profile, ECH wave amplitude, and temperature/characteristic energy of electron distribution functions on the calculated diffuse auroral intensities. The proposed missions, joint NASA/ESA Jupiter Icy Moon Explorer and the present JUNO mission to Jupiter, would provide new data to constrain the ECH wave and other physical parameters near Ganymede. These should help confirm the findings of the present study.
► The study identified IR74371-70-1-1 and IR74371-46-1-1 as stable genotypes with high yield under varied environments that ranged from irrigated control to severe drought stress. ► IR36, IR64, and ...MTU1010, the three popular varieties grown on large holdings in rainfed areas but bred for irrigated ecosystem were not found promising in drought environments. ► Improved genotypes ARB6, ARB2, ARB5, ARB7, ARB8, RF5329, CB0-15-24, IR72667-16-1-B-B-3, IR74371-78-1-1, and IR55419-04, and drought-tolerant released varieties Tripuradhan, Annada, Kallurundkar, and Poornima performed well only in drought-stress environments. ► Identification of improved stable genotypes IR74371-70-1-1 and IR74371-46-1-1 and their release for cultivation by farmers will enable farmers to reap high yield and stable income.
High and stable yield of rainfed lowland rice is important for sustainable rice production and food security. Many varieties grown on large holdings in rainfed areas provide good yield under normal water availability but suffer high losses in the event of drought. From a set of 129 genotypes tested in shallow rainfed drought-prone environments at three locations in eastern India from 2005 to 2007, a subset of 39 genotypes that were tested for two or more years under favorable irrigated, moderate reproductive-stage drought stress, and severe reproductive-stage drought stress situations in 16 environments was selected for a GGE biplot analysis to identify genotypes that provide stable yield across environments. IR74371-70-1-1 and IR74371-46-1-1 were identified as stable genotypes showing high yield under varied environments across different sites. IR36, IR64, and MTU1010, the three popular varieties grown on large holdings in rainfed areas but bred for irrigated ecosystem, as well as improved genotypes CB2-458, DGI237, R1027-2282-2-1, RR272-21, IR67469-R-1-1, and IR66873-R-11-1, and varieties PMK1 and PMK2 released for rainfed ecosystems performed well only in irrigated non-stress environments and were not found promising in drought environments. Improved genotypes ARB6, ARB2, ARB5, ARB7, ARB8, RF5329, CB0-15-24, IR72667-16-1-B-B-3, IR74371-78-1-1, and IR55419-04, and drought-tolerant released varieties Tripuradhan, Annada, and Poornima performed well only in drought-stress environments. The identification of improved genotypes with ability to provide stable high yield across variable environments and their release for cultivation by farmers will enable farmers to reap high yield and stable income.
The present study deals with the material tailoring of Mg(NH
2
)
2
-2LiH through dual borohydrides: the reactive LiBH
4
and the non-reactive NaBH
4
. Furthermore, a pulverizer, as well as a catalyst ...FeTi, has been added in order to facilitate hydrogen sorption. Addition of LiBH
4
to LiNH
2
in a 1 : 3 molar ratio leads to the formation of Li
4
(BH
4
)(NH
2
)
3
which also acts as a catalyst. However, the addition of NaBH
4
doesn't lead to any compound formation but shows a catalytic effect. The onset dehydrogenation temperature of thermally treated Mg(NH
2
)
2
-2LiH/(Li
4
(BH
4
)(NH
2
)
3
-NaBH
4
) is 142 °C as against 196 °C for the basic material Mg(NH
2
)
2
-2LiH. However, with the FeTi catalyzed Mg(NH
2
)
2
-2LiH/(Li
4
(BH
4
)(NH
2
)
3
-NaBH
4
, it has been reduced to 120 °C. This is better than other similar amide/hydride composites where it is 149 °C (when the basic material is catalyzed with LiBH
4
). The FeTi catalyzed Mg(NH
2
)
2
-2LiH/(Li
4
(BH
4
)(NH
2
)
3
-NaBH
4
sample shows better de/re-hydrogenation kinetics as it desorbs 3.9 ± 0.04 wt% and absorbs nearly 4.1 ± 0.04 wt% both within 30 min at 170 °C (with the H
2
pressure being 0.1 MPa for desorption and 7 MPa for absorption). The eventual hydrogen storage capacity of Mg(NH
2
)
2
-2LiH/(Li
4
(BH
4
)(NH
2
)
3
-NaBH
4
together with FeTi has been found to be ∼5.0 wt%. To make the effect of catalysts intelligible, we have put forward in a schematic way the role of Li and Na borohydrides with FeTi for improving the hydrogen sorption properties of Mg(NH
2
)
2
-2LiH.
The present study deals with the material tailoring of Mg(NH
2
)
2
-2LiH through dual borohydrides: the reactive LiBH
4
and the non-reactive NaBH
4
.
Nonstoichiometric (Cu
2−
x
Se) and stoichiometric (CuSe, β-Cu
2Se and Cu
2Se) copper selenide hexagonal nanoplates have been synthesized using different general and convenient copper sources, e.g. ...copper chloride, copper sulphate, copper nitrate, copper acetate, elemental copper with elemental selenium, friendly ethylene glycol and hydrazine hydrate in a defined amount of water at 100
°C within 12
h adopting the solvothermal method. Phase analysis, purity and morphology of the product have been well studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray diffraction (EDAX) techniques. The structural and compositional analysis revealed that the products were of pure phase with corresponding atomic ratios. SEM, TEM and HRTEM analyses revealed that the nanoplates were in the range 200–450
nm and the as-prepared products were uniform and highly crystallized. The nanoplates consisted of {0
0
1} facets of top–bottom surfaces and {1
1
0} facets of the other six side surfaces. This new approach encompasses many advantages over the conventional solvothermal method in terms of product quality (better morphology control with high yield) and reaction conditions (lower temperatures). Copper selenide hexagonal nanoplates obtained by the described method could be potential building blocks to construct functional devices and solar cell. This work may open up a new rationale on designing the solution synthesis of nanostructures for materials possessing similar intrinsic crystal symmetry. On the basis of the carefully controlled experiments mentioned herein, a plausible formation mechanism of the hexagonal nanoplates was suggested and discussed. To the best of our knowledge, this is the first report on nonstoichiometric (Cu
2−
x
Se) as well as stoichiometric (CuSe, β-Cu
2Se and Cu
2Se) copper selenide hexagonal nanoplates with such full control of morphologies and phases by this method under mild conditions.
An efficient method for the attachment of biomolecules e.g. bovine serum albumin (BSA) protein and deoxyribonucleic acid (DNA) to amino-group-functionalized multiwalled carbon nanotubes (f-MWCNTs) ...was reported. MWCNTs were prepared by spray pyrolysis of a benzene-ferrocene solution in argon atmosphere at ∼850 °C followed by functionalization with an amino group by chemical modification of carboxylic groups introduced on the nanotube surface. This process involves a direct coupling of ethylenediamine with carboxylic groups to introduce amino groups by amide formation. The as-synthesized MWCNTs, f-MWCNTs, and amino f-MWCNTs with BSA protein and DNA were characterized by scanning and transmission electron microscopy, and Fourier transform infrared spectroscopy, which confirm the attachment of biomolecules (BSA protein and DNA) to the amino f-MWCNTs.
To explore the practical feasibility of exotic carbon, various types of geometries of CNT configurations have been investigated such as CNT film, vertically aligned nanotubes, 3D pillared ...graphene-CNT network etc. High-performance and applicability of CNT derived electrodes in electrochemical energy storage depend on the structural design and high aspect ratio geometry. Here, we have strategically designed electrode derived from a special type of 3D geometry known as carbon hollow cylinders (CHCs) made up of CNTs arranged in the radial direction. The exceptional geometry provides a high areal capacity of 513.92 C/cm2 at an applied current density of 16 mA/cm2. Also, high specific energy of 41.13 mWh/cm2 at the specific power of 5694.92 mW/cm2 originated from supercapacitors and battery response of the electrode material was attained, which idealized the fundamental of theory of composite type electrode material. Hence, proposed geometry sets a stepping stone for a paradigm shift in light-weight electrode which is not only binder-free but also designed with a special geometry that provides an exceptional higher areal capacity with stable network.
A field experiment was conducted on weed management in aerobic rice (Oryza sativa L.) cultivation during dry season in 2013, 2014 and 2015. Efficacy of different weed management tools was compared ...for their weed suppression ability in the cultivation of an improved rice variety, Sahbhagi Dhan at aerobic soil situations. The study showed highest (around 60%) weed control efficiency (WCE) and lowest (around 15%) weed index (WI) with intensive weed management (IWM), which was, however, found an uneconomical option on account of higher cost of weed management. The most economically viable weed management tool was the combined practice of the application of pre-emergence weedicide, Butachlor @ 2.5 l/ha after three days of sowing followed by manual weeding at 4th week stage of crop growth accounting around 35% WCE and 22.12% WI. Grain yield was recorded significantly higher (3.70 - 3.89 t/ha) with IWM followed by 3.61 - 3.62 t/ha with twice manual weeding. However, combined practice of pre-emergence weedicide application followed by manual weeding, although produced comparatively less grain yield of 3.47 - 3.50 t/ha, resulted in higher net return of Rupees 15250.0 and B:C ratio of 1.48 for the lowest cost of weed management (Rupees 6075.0). Thus, the study could suggest the application of pre-emergence weedicide supplemented with one manual weeding as the efficient weed management tool that could effectively control weed population inaerobic rice cultivation.
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