215 research outputs found
Performance Evaluation of \u3cem\u3eKharif\u3c/em\u3e and \u3cem\u3eRabi\u3c/em\u3e Fodder Sorghum in Namsai District of Arunachal Pradesh
Deficiency of feed and fodder accounts for half of the total loss in dairy farming therefore, forages are called as backbone of livestock industry. The scarcity of green forages and grazing resources in the country has made the livestock to suffer continuously with malnutrition resulting in their production potentiality at sub-optimum level as compared to many developed nations (Anonymous, 2012). Arunachal Pradesh is well known for its ever green vegetation and biodiversity under hilly ecosystem. Though, it is situated at remotest part of country but possess huge scope of livestock farming. Namsai district of Arunachal Pradesh is a bordering district of Assam and having huge potential of milk production and its marketing which may help to improve the economic condition and poverty eradication of rural people. Cow is a major dairy animal here, however, the milk production capacity is very low as compared to other parts of the country. Dairy cow are reared in century old traditional way therefore, there are several areas of dairy management which needs improvement. Scarcity of feed and fodder is one of the major bottleneck which needs to be addressed urgently. Namsai district has very limited number of fodder crop and farmers mainly depend on non-conventional, public grazing land and forest vegetation. KVK Lohit (Namsai district) has introduced fodder sorghum in rainy and winter season for the first time in the district purposefully to improve the fodder availability under organized dairy farming in Namsai district
Single Crystal Growth and Characterization of the Iron-Based Superconductor KFe2As2 Synthesized by KAs Flux Method
Centimeter sized platelet single crystals of KFe2As2 were grown using a
self-flux method. An encapsulation technique using commercial stainless steel
container allowed the stable crystal growth lasting for more than 2 weeks.
Ternary K-Fe-As systems with various starting compositions were examined to
determine the optimal growth conditions. Employment of KAs flux led to the
growth of large single crystals with the typical size of as large as 15 mm x 10
mm x 0.4 mm. The grown crystals exhibit sharp superconducting transition at 3.4
K with the transition width 0.2 K, as well as the very large residual
resistivity ratio exceeding 450, evidencing the good sample quality.Comment: 4 pages, 6 Postscript figure
Chemical Pressure and Physical Pressure in BaFe_2(As_{1-x}P_{x})_2
Measurements of the superconducting transition temperature, T_c, under
hydrostatic pressure via bulk AC susceptibility were carried out on several
concentrations of phosphorous substitution in BaFe_2(As_{1-x}P_x)_2. The
pressure dependence of unsubstituted BaFe_2As_2, phosphorous concentration
dependence of BaFe_2(As_{1-x}P_x)_2, as well as the pressure dependence of
BaFe_2(As_{1-x}P_x)_2 all point towards an identical maximum T_c of 31 K. This
demonstrates that phosphorous substitution and physical pressure result in
similar superconducting phase diagrams, and that phosphorous substitution does
not induce substantial impurity scattering.Comment: 5 pages, 4 figures, to be published in Journal of the Physical
Society of Japa
Determination of the Upper Critical Field of a Single Crystal LiFeAs: The Magnetic Torque Study up to 35 Tesla
We report on the upper critical field B_c2 of a superconducting LiFeAs single
crystal with T_c~16 K, determined from magnetic torque measurements in
dc-magnetic fields up to 35 T and at temperatures down to 0.3 K. B_c2 at 0.3 K
is obtained to be 26.4 T and 15.5 T for the applied field B_a||ab and B_a||c,
respectively. The anisotropy parameter = is ~ 3 at
T_c and decreases to 1.7 as , showing rather isotropic
superconductivity. While B_c2 is orbitally-limited for B_a||c, the
spin-paramagnetic effect is evident in the temperature dependence of B_c2 for
B_a||abComment: 4 pages, 4 figures, revised version to be published in J. Phys. Soc.
Jpn. as a letter articl
Iron pnictides: Single crystal growth and effect of doping on structural, transport and magnetic properties
We demonstrate the preparation of large, free standing iron pnictide single
crystals with a size up to 20 x 10 x 1 mm3 using solvents in zirconia crucibles
under argon atmosphere. Transport and magnetic properties are investigated to
study the effect of potassium doping on the structural and superconducting
property of the compounds. The spin density wave (SDW) anomaly at Ts ~138 K in
BaFe2As2 single crystals from self-flux shifts to Ts ~85 K due to Sn solvent
growth. We show direct evidence for an incorporation of Sn on the Fe site. The
electrical resistivity data show a sharp superconducting transition temperature
Tc~38.5 K for the single crystal of Ba0.68K0.32Fe2As2. A nearly 100% shielding
fraction and bulk nature of the superconductivity for the single crystal were
confirmed by magnetic susceptibility data. A sharp transition Tc~25 K occurred
for the single crystal of Sr0.85K0.15Fe2As2. There is direct evidence for a
coexistence of the SDW and superconductivity in the low doping regime of
Sr1-xKxFe2As2 single crystals. Structural implications of the doping effects as
well as the coexistence of the two order parameters are discussed.Comment: 22 pages, 9 figure
IMPACT OF OZONE CONCENTRATION ON OCEAN COLOUR RETRIEVALS FOR OCM-2
Ozone being an absorbing gas have a significant impact on OCM-2 bands 510 nm, 555 nm and 620 nm which are using for retrieval of major geophysical parameters like Chlorophyll and suspended sediment concentrations. A study has been carried out to analyse the impact of Ozone concentration by ingesting near real time from OMI (Ozone Monitoring Instrument) on Aura instead of Climatology V2013 (2004–13) with a resolution of 1 × 1 deg for ocean colour retrievals from OCM-2 sensor using SeaWiFS Data Analysis System (SeaDAS). The spectral behaviour of Ozone transmittance has been studied for various bands of OCM-2 by using both Climatology and near real time inputs. We could observe maximum relative error percentage about 12 % from Climatology to NRT in Ozone concentration and 0.28 %, 0.66 % and 0.72 % of maximum mean relative error in ozone transmittance at 512 nm, 557 nm and 620 nm. We calculated error budgets induced by ozone in remote sensing reflectance(/sr) where in we could observe mean relative error percentage of 0.52 % in 491 nm, 1.12 % in 512 nm and 4.28 % 557 nm a bands respectively
To What Extent Iron-Pnictide New Superconductors Have Been Clarified: A Progress Report
In this review, the authors present a summary of experimental reports on
newly discovered iron-based superconductors as they were known at the end of
2008. At the same time, this paper is intended to be useful for experimenters
to know the current status of these superconductors. The authors introduce
experimental results that reveal basic physical properties in the normal and
superconducting states. The similarities and differences between iron-pnictide
superconductors and other unconventional superconductors are also discussed.Comment: 20 pages, 32 figures. Open selec
Single crystals of LnFeAsO1-xFx (Ln=La, Pr, Nd, Sm, Gd) and Ba1-xRbxFe2As2: growth, structure and superconducting properties
A review of our investigations on single crystals of LnFeAsO1-xFx (Ln=La, Pr,
Nd, Sm, Gd) and Ba1-xRbxFe2As2 is presented. A high pressure technique has been
applied for the growth of LnFeAsO1-xFx crystals, while Ba1-xRbxFe2As2 crystals
were grown using quartz ampoule method. Single crystals were used for
electrical transport, structure, magnetic torque and spectroscopic studies.
Investigations of the crystal structure confirmed high structural perfection
and show less than full occupation of the (O, F) position in superconducting
LnFeAsO1-xFx crystals. Resistivity measurements on LnFeAsO1-xFx crystals show a
significant broadening of the transition in high magnetic fields, whereas the
resistive transition in Ba1 xRbxFe2As2 simply shifts to lower temperature.
Critical current density for both compounds is relatively high and exceeds
2x109 A/m2 at 15 K in 7 T. The anisotropy of magnetic penetration depth,
measured on LnFeAsO1-xFx crystals by torque magnetometry is temperature
dependent and apparently larger than the anisotropy of the upper critical
field. Ba1-xRbxFe2As2 crystals are electronically significantly less
anisotropic. Point-Contact Andreev-Reflection spectroscopy indicates the
existence of two energy gaps in LnFeAsO1-xFx. Scanning Tunneling Spectroscopy
reveals in addition to a superconducting gap, also some feature at high energy
(~20 meV).Comment: 27 pages, 19 figures, 2 tables, accepted to the special issue of the
Physica C on superconducting pnictide
Distorted magnetic orders and electronic structures of tetragonal FeSe from first-principles
We use the state-of-the-arts density-functional-theory method to study
various magnetic orders and their effects on the electronic structures of the
FeSe. Our calculated results show that, for the spins of the single Fe layer,
the striped antiferromagnetic orders with distortion are more favorable in
total energy than the checkerboard antiferromagnetic orders with tetragonal
symmetry, which is consistent with known experimental data, and the inter-layer
magnetic interaction is very weak. We investigate the electronic structures and
magnetic property of the distorted phases. We also present our calculated spin
coupling constants and discuss the reduction of the Fe magnetic moment by
quantum many-body effects. These results are useful to understand the
structural, magnetic, and electronic properties of FeSe, and may have some
helpful implications to other FeAs-based materials
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