56,741 research outputs found
Impact of Organic Farming on Yield and Quality of BASMATI Rice and Soil Properties
The management of soil organic matter is critical to maintain a productive organic farming system. No one source of nutrient usually suffices to maintain productivity and quality control in organic system. In addition, the inputs to supplement nutrient avail-ability are often not uniform presenting additional challenges in meeting the nutrient requirement of crops in organic systems. With this concept, a field experiment was conducted at the research farm of Indian Agricultural Research Institute, New Delhi, India during 2003-06 in rice-wheat-green gram cropping system. In this experiment, different treatments comprising organic amendments such as Blue Green Algae (BGA) 15kg/ha, Azolla 1.0 tonne/ha, Vermicompost and Farm Yard Manure (FYM) 5.0 tonne/ha each applied alone or in combination were tested in organic crop production. These treatments were compared with absolute control (N0P0K0) and recommended dose of chemical fertilizer (N80P40K40). In wheat crop Azotobacter replaced Azolla, but other treatments remained same. For rice, a scented variety ‘Pusa Basmati 1’ and for wheat and green gram HYVs were taken. Biomass of green gram was incorporated in soil after picking of pods and wheat was sown using zero tillage practice. The obser-vations on grain yield, contents of Fe, Zn, Mn and Cu in rice grains, insect pest inci-dence, soil nutrients and microbial activity were taken.
Results revealed a significant enhancement in grain yield of rice over absolute control due to the application of different organic amendments applied alone or in combina-tions. Rice grain yield increased by 114 to 116.8% over absolute control when all the 4 organic amendments were applied altogether. The rice grain yield (4.0 t ha-1) obtained under combined application of four organic amendments was at par with the yield recorded under recommended dose of chemical fertilizer application. An interesting observation recorded was that there was no serious attack of any insect pest or dis-ease in organically grown crop. Soil microbial population (Actinomycetes, Bacteria, Fungi and BGA) enhanced due to the application of organic amendments in compari-son to absolute control as well as recommended fertilizer application that in turn re-sulted in a notable enhancement in soil dehydrogenase and phosphatase enzyme activity. Soil organic carbon and available phosphorus contents were also found to be significantly increased due to organic farming practice over control as well as chemical fertilizer application.
Rice grain analysis for nutrients viz. Fe, Zn, Mn and Cu showed a significant increase in Fe and Mn content in the treatments having 2 or more organic amendments over control. Zn and Cu content also increased but the increment was significant with combined application of 3 or 4 organic amendments.
The study revealed that addition of four organic amendments viz. BGA, Azolla, FYM and Vermicompost could give the optimum yield (4.05 t/ha) of organic Basmati rice and improve grain and soil quality
Bulk superconductivity in Bi4O4S3 revealed by specific heat measurement
Specific heat experiments on a well-characterized polycrystalline sample of
the BiS2 based superconductor Bi4O4S3 revealed that it shows a crear specific
heat anomaly at about Tc = 4.4 K, consistent with Tc from the resistivity and
dc susceptibility. This observation indicates the superconductivity of Bi4O4S3
to be bulk in nature
Force-induced desorption of a linear polymer chain adsorbed on an attractive surface
We consider a model of self-avoiding walk on a lattice with on-site repulsion
and an attraction for every vertex of the walk visited on the surface to study
force-induced desorption of a linear polymer chain adsorbed on an attractive
surface and use the exact enumeration technique for analyzing how the critical
force for desorption depends on the temperature. The curve
gives the boundary separating the adsorbed phase from the desorbed phase. Our
results show that in two dimensions where surface is a line the force
increases monotonically as temperature is lowered and becomes almost constant
at very low temperatures. In case of three-dimensions we, however, find
re-entrance, i. e. goes through a maximum as temperature is lowered.
The behaviour of the polymer chain at different values of temperature and force
is examined by calculating the probability distribution of the height from the
surface of the vertex at which external force is applied.Comment: Preprint 15 pages with 8figures and two tables. The file table-2d.ps
and table-3d.ps lists C_N(Ns,h) for given N with all possible Ns and h in two
and three dimension
Superconductivity in a new hexagonal high entropy alloy
High entropy alloys (HEAs) are the new class of materials with an attractive
combination of tunable mechanical and physicochemical properties. They
crystallize mainly in cubic structures, however, for practical applications,
HEAs with hexagonal close-packed (hcp) structure are highly desirable in
connection to their in general high hardness. Herein, we report the synthesis,
structure and detailed superconducting properties of
ReNbTiZrHf-the first hexagonal
superconducting high entropy alloy (HEA) composed of five randomly distributed
transition-metals. Combination of room temperature precession electron
diffraction, precession electron diffraction tomography and powder X-ray
diffraction is utilized to determine the room temperature crystal structure.
Transport, magnetic and heat capacity measurements show that the material is a
type-II superconductor with the bulk superconducting transition at =
4.4 K, lower critical field (0) = 2.3 mT and upper critical field
(0) = 3.6 T. Low-temperature specific heat measurement indicates that
ReNbTiZrHf is a phonon-mediated
superconductor in the weak electron-phonon coupling limit with a normalized
specific heat jump = 1.32. Further,
hexagonal to cubic structural transition is observed by lowering the valence
electron counts and follows crystalline-like behaviour.Comment: 6 Pages, 9 Figures. arXiv admin note: text overlap with
arXiv:1804.1009
Long-range interacting many-body systems with alkaline-earth-metal atoms
Alkaline-earth-metal atoms exhibit long-range dipolar interactions, which are
generated via the coherent exchange of photons on the 3P_0-3D_1-transition of
the triplet manifold. In case of bosonic strontium, which we discuss here, this
transition has a wavelength of 2.7 \mu m and a dipole moment of 2.46 Debye, and
there exists a magic wavelength permitting the creation of optical lattices
that are identical for the states 3P_0 and 3D_1. This interaction enables the
realization and study of mixtures of hard-core lattice bosons featuring
long-range hopping, with tuneable disorder and anisotropy. We derive the
many-body Master equation, investigate the dynamics of excitation transport and
analyze spectroscopic signatures stemming from coherent long-range interactions
and collective dissipation. Our results show that lattice gases of
alkaline-earth-metal atoms permit the creation of long-lived collective atomic
states and constitute a simple and versatile platform for the exploration of
many-body systems with long-range interactions. As such, they represent an
alternative to current related efforts employing Rydberg gases, atoms with
large magnetic moment, or polar molecules
The dependence of the estimated luminosities of ULX on spectral models
Data from {\it Chandra} observations of thirty nearby galaxies were analyzed
and 365 X-ray point sources were chosen whose spectra were not contaminated by
excessive diffuse emission and not affected by photon pile up. The spectra of
these sources were fitted using two spectral models (an absorbed power-law and
a disk blackbody) to ascertain the dependence of estimated parameters on the
spectral model used. It was found that the cumulative luminosity function
depends on the choice of the spectral model, especially for luminosities ergs/s. In accordance with previous results, a large number () of the sources have luminosities ergs/s (Ultra-Luminous X-ray
sources) with indistinguishable average spectral parameters (inner disk
temperature keV and/or photon index ) with those of the
lower luminosities ones. After considering foreground stars and known
background AGN,we identify four sources whose minimum luminosity exceed
ergs/s, and call them Extremely Luminous X-ray sources (ELX). The
spectra of these sources are in general better represented by the disk black
body model than the power-law one. These ELX can be grouped into two distinct
spectral classes. Two of them have an inner disk temperature of keV and
hence are called ``supersoft'' ELX, while the other two have temperatures
keV and are called ``hard'' ELX. The estimated inner disk
temperatures of the supersoft ELX are compatible with the hypothesis that they
harbor intermediate size black holes, which are accreting at times
their Eddington Luminosity. The radiative mechanism for hard ELX, seems to be
Inverse Comptonization, which in contrast to standard black holes systems, is
probably saturated.Comment: Accepted for publication in Astrophysical Journal. 9 pages. Complete
long Tables 4 and 5 are given as tab4.tex and tab5.tex separatel
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