553 research outputs found
Toxicity of four therapeutic compounds to fry of Indian major carps
Toxicity of four therapeutic compounds: sodium chloride, potassium permanganate, potassium dichromate and acriflavine to fry of Catla calla, Labeo rohita and Cirrhinus mrigala was tested. Bioassays were conducted in 5 and 10 liters glass jars in the laboratory for periods of 24-48 hrs. at temperatures of 26° and 32°C. LC 50 values of the chemicals were in the ranges of 5500 to 7500 ppm, 37.5 to 48 ppm, 92.5 to 125 ppm and 47.5 to 80 ppm respectively. The results obtained are of value in evolving cheap control methods against some common fish diseases. Sodium chloride and acriflavine can be widely used for chemotherapy and potassium dichromate is preferable to potassium permanganate for prophylaxis
Creep Modelling of P91 Steel for High Temperature Power Plant Applications
AbstractThere has been considerable interest in the development of continuum damage (CDM) mechanism based model for creep life predictions of 9CrMoNbV steel. It is reported that the steel has high dislocation density in normalized and tempered condition whereas with creep exposure it goes down significantly. The paper examines one of the recent models and attempts to incorporate this as an additional damage parameter. This has resulted in much better prediction of creep stain time plots for this steel
Transient Approach to Radiative Heat Transfer Free Convection Flow with Ramped Wall Temperature
The effect of radiation on natural convection incompressible viscous fluid near a vertical flat plate with ramped wall
temperature has been studied. An analytical solution of the governing equation has been obtained by employing
Laplace transform technique. It is examined that two different solutions for the fluid velocities, one valid for fluids of
Prandtl number Pr different from 1 Ra , Ra being the radiation parameter and the other for which the Prandtl
number equal to 1 Ra . The variations of velocities and fluid temperature are presented graphically. Furthermore,
the radiative heat transfer on natural convection flow near a ramped plate temperature has been compared with the
flow near a plate with the constant wall temperature. It is found that an increase in radiation parameter leads to rise
the fluid velocity as well as temperature
Wormhole with varying cosmological constant
It has been suggested that the cosmological constant is a variable dynamical
quantity. A class of solution has been presented for the spherically symmetric
space time describing wormholes by assuming the erstwhile cosmological constant
to be a space variable scalar, viz., = . It
is shown that the Averaged Null Energy Condition (ANEC) violating exotic matter
can be made arbitrarily small.Comment: 8 pages, 2 figures, Accepted in Gen. Rel. Gra
Magnetic field and pressure effects on charge density wave, superconducting, and magnetic states in LuIrSi and ErIrSi
We have studied the charge-density-wave (CDW) state for the superconducting
LuIrSi and the antiferromagnetic ErIrSi as
variables of temperature, magnetic field, and hydrostatic pressure. For
LuIrSi, the application of pressure strongly suppresses the CDW
phase but weakly enhances the superconducting phase. For ErIrSi,
the incommensurate CDW state is pressure independent and the commensurate CDW
state strongly depends on the pressure, whereas the antiferromagnetic ordering
is slightly depressed by applying pressure. In addition, ErIrSi
shows negative magnetoresistance at low temperatures, compared with the
positive magnetoresistance of LuIrSi.Comment: 12 pages, including 6 figure
Modulational instability of ion-acoustic wave packets in quantum pair-ion plasmas
Amplitude modulation of quantum ion-acoustic waves (QIAWs) in a quantum
electron-pair-ion plasma is studied. It is shown that the quantum coupling
parameter (being the ratio of the plasmonic energy density to the Fermi
energy) is ultimate responsible for the modulational stability of QIAW packets,
without which the wave becomes modulational unstable. New regimes for the
modulational stability (MS) and instability (MI) are obtained in terms of
and the positive to negative ion density ratio . The growth rate of MI
is obtained, the maximum value of which increases with and decreases
with . The results could be important for understanding the origin of
modulated QIAW packets in the environments of dense astrophysical objects,
laboratory negative ion plasmas as well as for the next generation laser solid
density plasma experiments.Comment: 4 pages, 2 figures (to appear in Astrophysics and Space Science
Tuned mass damper effects on the response of multi-storied structures observed in geotechnical centrifuge tests
Tuned mass dampers (TMDs) are widely used to reduce vibrations in structures. However, very little research is available on the experimental investigation of TMDs and their performance in soilstructure systems. In this paper, a series of geotechnical centrifuge tests was conducted to investigate the effects of TMDs on the response of a multiple-storey sway frame structure undergoing dynamic soil-structure interaction (SSI). Structural responses were recorded for a wide range of input motion characteristics, damper configurations and soil profiles. The practicality associated with the use of TMDs in the damping of resonant structures in light of unexpected earthquake characteristics different from design earthquakes was experimentally demonstrated. Tuning a TMD to soil-structure system properties rather than fixed-base structural properties was found to double the improvement in damping and reduce the original peak response by nearly half. The potential effectiveness of a detuned mass damper in light of significant SSI was also demonstrated.The financial help during the course of the study was extended by the Engineering and Physical Sciences Research Council (EPSRC).This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.soildyn.2015.06.01
A Honeycomb Proportional Counter for Photon Multiplicity Measurement in the ALICE Experiment
A honeycomb detector consisting of a matrix of 96 closely packed hexagonal
cells, each working as a proportional counter with a wire readout, was
fabricated and tested at the CERN PS. The cell depth and the radial dimensions
of the cell were small, in the range of 5-10 mm. The appropriate cell design
was arrived at using GARFIELD simulations. Two geometries are described
illustrating the effect of field shaping. The charged particle detection
efficiency and the preshower characteristics have been studied using pion and
electron beams. Average charged particle detection efficiency was found to be
98%, which is almost uniform within the cell volume and also within the array.
The preshower data show that the transverse size of the shower is in close
agreement with the results of simulations for a range of energies and converter
thicknesses.Comment: To be published in NIM
The STAR Photon Multiplicity Detector
Details concerning the design, fabrication and performance of STAR Photon
Multiplicity Detector (PMD) are presented. The PMD will cover the forward
region, within the pseudorapidity range 2.3--3.5, behind the forward time
projection chamber. It will measure the spatial distribution of photons in
order to study collective flow, fluctuation and chiral symmetry restoration.Comment: 15 pages, including 11 figures; to appear in a special NIM volume
dedicated to the accelerator and detectors at RHI
Scenario of Accelerating Universe from the Phenomenological \Lambda- Models
Dark matter, the major component of the matter content of the Universe,
played a significant role at early stages during structure formation. But at
present the Universe is dark energy dominated as well as accelerating. Here,
the presence of dark energy has been established by including a time-dependent
term in the Einstein's field equations. This model is compatible with
the idea of an accelerating Universe so far as the value of the deceleration
parameter is concerned. Possibility of a change in sign of the deceleration
parameter is also discussed. The impact of considering the speed of light as
variable in the field equations has also been investigated by using a well
known time-dependent model.Comment: Latex, 9 pages, Major change
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