Sona,Kundukulam O; Manju,Paulson; Aanandan,C K; Mohanan, P(Microwave Engineering Group,Department of Electronics, April 20, 2002)
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Abstract:
Design equations are presented for calculating the resonance frequencies for a
compact dual frequency arrow-shaped microstrip antenna. This provides a fast and simple
way to predict the resonant frequencies of the antenna. The antenna is also analyzed using the
IE3D simulation package. The theoretical predictions are found to be very close to the
IE3D results and thus establish the validity of the design formulae
Alice, Mathai; Dr.Nandakumar, C G(Cochin University of Science & Technology, November , 2004)
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Abstract:
Submarine hull structure is a watertight envelope, under hydrostatic pressure
when in operation. Stiffened cylindrical shells constitute the major portion of these
submarine hulls and these thin shells under compression are susceptible to buckling
failure. Normally loss of stability occurs at the limit point rather than at the
bifurcation point and the stability analysis has to consider the change in geometry at
each load step. Hence geometric nonlinear analysis of the shell forms becomes. a
necessity. External hydrostatic pressure will follow the deformed configuration of the
shell and hence follower force effect has to be accounted for.
Computer codes have been developed based on all-cubic axisymmetric
cylindrical shell finite element and discrete ring stiffener element for linear elastic,
linear buckling and geometric nonIinear analysis of stiffened cylindrical shells. These
analysis programs have the capability to treat hydrostatic pressure as a radial load
and as a follower force.
Analytical investigations are carried out on two attack submarine cylindrical
hull models besides standard benchmark problems. In each case, the analysis has
been carried out for interstiffener, interdeepframe and interbulkhead configurations.
The shell stiffener attachment in each of this configuration has been represented by
the simply supported-simply supported, clamped-clamped and fixed-fixed boundary
conditions in this study.
The results of the analytical investigations have been discussed and the
observations and conclusions are described. Rotation restraint at the ends is
influential for interstiffener and interbulkhead configurations and the significance of
axial restraint becomes predominant in the interbulkhead configuration. The follower
force effect of hydrostatic pressure is not significant in interstiffener and
interdeepframe configurations where as it has very high detrimental effect on
buckling pressure on interbulkhead configuration. The geometric nonlinear
interbulkhead analysis incorporating follower force effect gives the critical value of
buckling pressure and this analysis is recommended for the determination of collapse
pressure of stiffened cylindrical submarine shells.
Description:
Dept.of Ship Technology,Cochin University of Science & Technology
Rajagopalan, S; Dr. Sabir, M(Cochin University Of Science And Technology, March 4, 2002)
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Abstract:
The study of simple chaotic maps for non-equilibrium processes in statistical
physics has been one of the central themes in the theory of chaotic dynamical
systems. Recently, many works have been carried out on deterministic diffusion
in spatially extended one-dimensional maps This can be related to real physical
systems such as Josephson junctions in the presence of microwave radiation and
parametrically driven oscillators. Transport due to chaos is an important problem
in Hamiltonian dynamics also. A recent approach is to evaluate the exact diffusion
coefficient in terms of the periodic orbits of the system in the form of cycle
expansions. But the fact is that the chaotic motion in such spatially extended maps
has two complementary aspects- - diffusion and interrnittency. These are related
to the time evolution of the probability density function which is approximately
Gaussian by central limit theorem. It is noticed that the characteristic function
method introduced by Fujisaka and his co-workers is a very powerful tool for
analysing both these aspects of chaotic motion. The theory based on characteristic
function actually provides a thermodynamic formalism for chaotic systems
It can be applied to other types of chaos-induced diffusion also, such as the one
arising in statistics of trajectory separation. It was noted that there is a close connection
between cycle expansion technique and characteristic function method. It
was found that this connection can be exploited to enhance the applicability of
the cycle expansion technique. In this way, we found that cycle expansion can be
used to analyse the probability density function in chaotic maps. In our research
studies we have successfully applied the characteristic function method and cycle
expansion technique for analysing some chaotic maps. We introduced in this
connection, two classes of chaotic maps with variable shape by generalizing two
types of maps well known in literature.
Description:
Department of Physics, Cochin University of Science and Technology
Choudhury, P K; Roger, Lessard S(Microwave and Optical Technology Letters, January 20, 2002)
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Abstract:
An attempt is made to determine the relative power
distribution in a step-index parabolic cylindrical waveguide (PCW) with
high deformation across the direction of propagation. The guide is
assumed to be made of silica. The scalar field approximation is employed
for the analysis under which a vanishing refractive-index (RI) difference
in the waveguide materials is considered. Further, no approximation for
folds- is used in the analytical treatment. Due to the geometry of such
waceguides, PCWs lose the well-defined modal discreteness, and a kind
of mode bunching is observed instead, which becomes much more
prominent in PCWs with high bends. However, with the increase in
cross-sectional size, the mode-bunching tendency is slightly reduced. The
general expressions for power in the guiding and nonguiding sections are
obtained, and the fractional power patterns in all of the sections are
presented for PCWs of various cross-sectional dimensions. It is observed
that the confinement of power in the core section is increased for PCWs
of larger cross-sectional size. Moreover, a fairly uniform distribution of
power is seen over the modes having intermediate values of propagation
constants
Sheeja, N K; Santhosh Kumar, G; Humayoon Kabir, S; Surendran, Cherukodan(INFLIBNET Centre, March , 2013)
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Abstract:
The present study is an attempt to highlight the problem of typographical errors in OPACS. The
errors made while typing catalogue entries as well as importing bibliographical records from other
libraries exist unnoticed by librarians resulting the non-retrieval of available records and affecting
the quality of OPACs. This paper follows previous research on the topic mainly by Jeffrey Beall and
Terry Ballard. The word “management” was chosen from the list of likely to be misspelled words
identified by previous research. It was found that the word is wrongly entered in several forms in
local, national and international OPACs justifying the observations of Ballard that typos occur in
almost everywhere. Though there are lots of corrective measures proposed and are in use, the study
asserts the fact that human effort is needed to get rid of the problem. The paper is also an invitation
to the library professionals and system designers to construct a strategy to solve the issue
Description:
9th International CALIBER - 2013, INFLIBNET Centre, Gandhinagar, Gujarat, March 21-23, 2013
Santhosh Kumar, G; Surendran, Cherukodan; Sheeja, N K; Humayoon Kabir, S(INFLIBNET Centre, Ahmedabad, 2013)
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Abstract:
The present study is an attempt to highlight the problem of typographical errors in OPACS. The
errors made while typing catalogue entries as well as importing bibliographical records from other
libraries exist unnoticed by librarians resulting the non-retrieval of available records and affecting
the quality of OPACs. This paper follows previous research on the topic mainly by Jeffrey Beall and
Terry Ballard. The word “management” was chosen from the list of likely to be misspelled words
identified by previous research. It was found that the word is wrongly entered in several forms in
local, national and international OPACs justifying the observations of Ballard that typos occur in
almost everywhere. Though there are lots of corrective measures proposed and are in use, the study
asserts the fact that human effort is needed to get rid of the problem. The paper is also an invitation
to the library professionals and system designers to construct a strategy to solve the issue
Description:
9th International CALIBER - 2013, INFLIBNET Centre, Gandhinagar, Gujarat, March 21-23, 2013
Poulose Jacob,K; David, Peter S; Sreela Sasi(June , 2006)
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Abstract:
This paper discusses the complexities involved in managing and monitoring the delivery of IT services in a multiparty outsourcing environment. The complexities identified are grouped into four categories and are tabulated. A discussion on an attempt to model a multiparty outsourcing scenario using UML is also presented and explained using an illustration. Such a model when supplemented by a performance evaluation tool can enable an organization to manage the provision of IT services in a multiparty outsourcing environment more effectively
Louis, Godfrey; Varughese, George; Santhosh Kumar, A; Philip, J(Indian Academy of Sciences, 2008)
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Abstract:
The double sulfate family (ABSO4), where A and B are alkali metal cations, is the object of great
interest owing to the complexity and richness of its sequence of phase transition induced by temperature
variation. A new sulfate salt characterized by the presence of water molecule in the unit cell with the chemical
formula, Li2Na3(SO4)2⋅6H2O (LSSW), was obtained. The ultrasonic velocity measurement was done with pulse
echo overlap technique [PEO]. All the six second order elastic stiffness constants, C11 = C22, C33, C44 = C55, C12,
C14 and C13 = C23 are reported for the first time. The anisotropy in the elastic properties of the crystal are well
explained by the pictorial representation of the polar plots of phase velocity, slowness, Young’s modulus and
linear compressibility in a–b and a–c planes.
Maya L Pai; Dr. A N Balchand; Dr. K V Pramod(Cochin University of Science and Technology, May 12, 2016)
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Abstract:
ANN based long range forecast of Indian summer monsoon rainfall for
the hydrological regions of India using ocean and atmosphere state
parameters with improved accuracy,Trend analysis of SST, sub surface temperature of Indian Ocean and
that of ISMR.
3. Prediction of extreme rainfall events using ANN.
Anantharaman, M R; Hysen, T; Salim, Al-Harthi; Al-Omari, I A; Geetha, P; Lisha, R; Ramanujan, R V; Sakthi Kumar, D(Elsevier, April 18, 2013)
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Abstract:
Co–Fe–Si based films exhibit high magnetic moments and are highly sought after for applications like soft under layer sinper pendicular recording mediatomagneto-electro-mechanical sensor applications.In this workt he effect of annealing on
s tructural,morphologicaland magnetic propertiesofco–Fe–Si thin films wasinvestigated.compositional analysis using x-rayphotoelectron spectroscopy and secondary ion massspectroscopyrevealedanativeoxidesurfacelayerconsistingofoxidesofco,feandsionthe surface. The morphology of theas deposited films shows mound like structures conformingtothe Volmer–Webergrowthmodel.Nanocrystallisationofamorphous films upon annealing was observed by glancing anglex-raydiffraction and transmission electron microscopy.Theevolutionofmagnetic properties with annealing is explained using the Herzermodel.Vibrating sample magnetometry measurements carried out at various angles from01 to 901 to the applied magnetic field were employed to study the angula rvariation of coercivity.The angular variation fits the modified Kondorsky model. Interestingly,the coercivity evolution with annealing deduced frommagneto-opticalKerreffectstudies indicates areversetrendcomparedtomagetisationobservedinthebulk.Thiscanbeattributedtoa domain wallpinningatnativeoxidelayeronthesurfaceofthin films. Theevolutionofsurfacemagnetic properties iscorrelatedwithmorphologyevolutionprobedusingatomicforcemicroscopy.The morphology aswellasthepresenceofthenativeoxidelayerdictatesthesurfacemagneticproperties and this is corroborated by the apparent difference in the bulk and surface magnetic properties
Riju, C Issac; Harilal, S S; Bindhu, C V; Geetha K, Varier; Nampoori, V P N; Vallabhan, C P G(Elsevier, 1997)
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Abstract:
A laser produced plasma from the multielement solid target YBa2Cu3O7 is generated using 1.06 μm, 9 ns pulses from a Q-switched Nd:YAG laser in air at atmospheric pressure. A time resolved analysis of the profile of the 4554.03 Å resonance line emission from Ba II at various laser power densities has been carried out. It has been found that the line has a profile which is strongly self-reversed. It is also observed that at laser power densities equal to or exceeding 1.6×1011 W cm−2, a third peak begins to develop at the centre of the self-reversed profile and this has been interpreted as due to the anisotropic resonance scattering (fluorescence). The number densities of singly ionized barium ions evaluated from the width of the resonance line as a function of time delay with respect to the beginning of the laser pulse give typical values of the order of 1019 cm−3. The higher ion concentrations existing at smaller time delays are seen to decrease rapidly. The Ba II ions in the ground state resonantly absorb the radiation and this absorption is maximum around 120 ns after the laser pulse.