8,095 research outputs found
Simultaneous Testing For the Goodness of Fit to Two or More Samples
In this paper we have considered the problem to test for the simultaneous goodness of fit of an absolutely continuous distribution function to many samples. The proposedtest is seen to have many desirable properties
Jacobi Crossover Ensembles of Random Matrices and Statistics of Transmission Eigenvalues
We study the transition in conductance properties of chaotic mesoscopic
cavities as time-reversal symmetry is broken. We consider the Brownian motion
model for transmission eigenvalues for both types of transitions, viz.,
orthogonal-unitary and symplectic-unitary crossovers depending on the presence
or absence of spin-rotation symmetry of the electron. In both cases the
crossover is governed by a Brownian motion parameter {\tau}, which measures the
extent of time-reversal symmetry breaking. It is shown that the results
obtained correspond to the Jacobi crossover ensembles of random matrices. We
derive the level density and the correlation functions of higher orders for the
transmission eigenvalues. We also obtain the exact expressions for the average
conductance, average shot-noise power and variance of conductance, as functions
of {\tau}, for arbitrary number of modes (channels) in the two leads connected
to the cavity. Moreover, we give the asymptotic result for the variance of
shot-noise power for both the crossovers, the exact results being too long. In
the {\tau} \rightarrow 0 and {\tau} \rightarrow \infty limits the known results
for the orthogonal (or symplectic) and unitary ensembles are reproduced. In the
weak time-reversal symmetry breaking regime our results are shown to be in
agreement with the semiclassical predictions.Comment: 24 pages, 5 figure
Correlation, Network and Multifractal Analysis of Global Financial Indices
We apply RMT, Network and MF-DFA methods to investigate correlation, network
and multifractal properties of 20 global financial indices. We compare results
before and during the financial crisis of 2008 respectively. We find that the
network method gives more useful information about the formation of clusters as
compared to results obtained from eigenvectors corresponding to second largest
eigenvalue and these sectors are formed on the basis of geographical location
of indices. At threshold 0.6, indices corresponding to Americas, Europe and
Asia/Pacific disconnect and form different clusters before the crisis but
during the crisis, indices corresponding to Americas and Europe are combined
together to form a cluster while the Asia/Pacific indices forms another
cluster. By further increasing the value of threshold to 0.9, European
countries France, Germany and UK constitute the most tightly linked markets. We
study multifractal properties of global financial indices and find that
financial indices corresponding to Americas and Europe almost lie in the same
range of degree of multifractality as compared to other indices. India, South
Korea, Hong Kong are found to be near the degree of multifractality of indices
corresponding to Americas and Europe. A large variation in the degree of
multifractality in Egypt, Indonesia, Malaysia, Taiwan and Singapore may be a
reason that when we increase the threshold in financial network these countries
first start getting disconnected at low threshold from the correlation network
of financial indices. We fit Binomial Multifractal Model (BMFM) to these
financial markets.Comment: 32 pages, 25 figures, 1 tabl
Bio-dissolution of metals from activated nodules of Indian Ocean
The biodissolution of valuable metals from ferro-manganese nodules of Indian Ocean in presence of Aspergillus niger is a slow process. In order to improve the kinetics of bioleaching, the sea nodules were activated in high energy attrition mill thereby changing the granulometry and surface charge characteristics of the particles. The zeta potential, particle size distribution and surface area of the activated material were recorded and bioleaching was carried out by A.niger in the pH range 4.0-5.5. The mechano-chemical activation of the mixed particles (≤ 75 µm) of nodules in 10 min reduced almost 86 % material to ≤ 10 µm size with a change in zeta potential from -18 to -34 mV. Bioleaching of metals from the activated nodules was compared with that of the dissolution pattern of metals in presence of A.niger without any pretreatment as well as those under the chemical leaching conditions. The results showed the bio-recovery of more than 95% copper, nickel and cobalt each in 15 days time when the nodules activated for 10 min was leached at 5 % (w/v) pulp density, 4.5 pH and 35 ºC temperature. Bio-leaching of these metals was observed to be similar from the nodules activated for 30 min. The non-activated nodules showed ≥ 89% metal recovery in 25 days under the above conditions. The mechano-chemical activation of sea nodules has thus been found to improve the kinetics of the process and has also resulted in to the availability of wider pH in the range of 4-5 for the processing
Conductance Distributions in Chaotic Mesoscopic Cavities
We consider the conductance distributions in chaotic mesoscopic cavities for
all three invariant classes of random matrices for the arbitrary number of
channels N1, N2 in the connecting leads. We show that the Laplace transforms of
the distributions can be expressed in terms of determinants in the unitary case
and Pfaffians in the orthogonal and symplectic cases. The inverse Laplace
transforms then give the exact distributions. This formalism is particularly
useful for small values of N = min (N1, N2), and thus is of direct experimental
relevance. We also obtain the conductance distributions for orthogonal-unitary
and symplectic-unitary crossover ensembles.Comment: 19 pages, 4 figure
Bioleaching - an alternate uranium ore processing technology for India
Meeting the feed supply of uranium fuel in the present and planned nuclear reactors calls for huge demand of uranium, which at the current rate of production, shows a mismatch. The processing methods at UCIL (DAE) needs to be modified/ changed or re-looked into because of its very suitability in near future for low-index raw materials which are either unmined or stacked around if mined. There is practically no way to process tailings with still some values. Efforts were made to utilize such resources (low-index ore of Turamdih mines, containing 0.03% U3O8) by NML in association with UCIL as a national endeavor. In this area, the R&D work showed the successful development of a bioleaching process from bench scale to lab scale columns and then finally to the India’s first ever large scale column, from the view point of harnessing such a processing
technology as an alternative for the uranium industry and nuclear sector in the country. The efforts culminated
into the successful operation of large scale trials at the 2ton level column uranium bioleaching that was carried
out at the site of UCIL, Jaduguda yielding a maximum recovery of 69% in 60 days. This achievement is expected to pave the way for scaling up the activity to a 100T or even more heap bioleaching trials for realization of this technology, which needs to be carried out with the support of the nuclear sector in the country keeping in mind the national interest
Amenability of low- grade uranium towards column bioleaching by acidithiobacillus ferrooxidans
ABSTRACT : R & D studies were carried out at NML using Acidithiobacillus ferrooxidans (Ac.TJ in
column for the bio-recovery of uranium from the low-grade uranium ore containing 0.024% U308 of
Turamdih Mines, Singhbhum. A recovery of 55 .48% uranium was obtained in bio-leaching as against --
44.0% in sterile control in 30 days at 1.7pH in a column containing 2 . 5kg ore of particle size mainly in the
ra,., 5-1mm . In the large scale column , leaching with 80kg ore of particle size -0.5cm, uranium biorecovery
was found to be 69.8% in comparison to a recovery of 55% in control set at 1.7 pH in 50 days. The
uranium recoveries followed indirect leaching mechanism
Small Quadrupole Deformation for the Dipole Bands in 112In
High spin states in In were investigated using Mo(O,
p3n) reaction at 80 MeV. The excited level have been observed up to 5.6 MeV
excitation energy and spin 20 with the level scheme showing three
dipole bands. The polarization and lifetime measurements were carried out for
the dipole bands. Tilted axis cranking model calculations were performed for
different quasi-particle configurations of this doubly odd nucleus. Comparison
of the calculations of the model with the B(M1) transition strengths of the
positive and negative parity bands firmly established their configurations.Comment: 10 pages, 11 figures, 2 table
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