Lalu, P P; Dr.Narayanan, K P(Cochin University Of Science And Technology, January , 2013)
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Abstract:
The motion instability is an important issue that occurs during the operation of towed
underwater vehicles (TUV), which considerably affects the accuracy of high precision
acoustic instrumentations housed inside the same. Out of the various parameters
responsible for this, the disturbances from the tow-ship are the most significant one. The
present study focus on the motion dynamics of an underwater towing system with ship
induced disturbances as the input. The study focus on an innovative system called two-part
towing. The methodology involves numerical modeling of the tow system, which consists
of modeling of the tow-cables and vehicles formulation. Previous study in this direction
used a segmental approach for the modeling of the cable. Even though, the model was
successful in predicting the heave response of the tow-body, instabilities were observed in
the numerical solution. The present study devises a simple approach called lumped mass
spring model (LMSM) for the cable formulation. In this work, the traditional LMSM has
been modified in two ways. First, by implementing advanced time integration procedures
and secondly, use of a modified beam model which uses only translational degrees of
freedoms for solving beam equation. A number of time integration procedures, such as
Euler, Houbolt, Newmark and HHT-α were implemented in the traditional LMSM and the
strength and weakness of each scheme were numerically estimated.
In most of the previous studies, hydrodynamic forces acting on the tow-system such as drag
and lift etc. are approximated as analytical expression of velocities. This approach restricts
these models to use simple cylindrical shaped towed bodies and may not be applicable
modern tow systems which are diversed in shape and complexity. Hence, this particular
study, hydrodynamic parameters such as drag and lift of the tow-system are estimated using
CFD techniques. To achieve this, a RANS based CFD code has been developed. Further, a
new convection interpolation scheme for CFD simulation, called BNCUS, which is blend of
cell based and node based formulation, was proposed in the study and numerically tested.
To account for the fact that simulation takes considerable time in solving fluid dynamic
equations, a dedicated parallel computing setup has been developed. Two types of computational parallelisms are explored in the current study, viz; the model for shared
memory processors and distributed memory processors. In the present study, shared
memory model was used for structural dynamic analysis of towing system, distributed
memory one was devised in solving fluid dynamic equations.
Description:
Department of Ship Technology
Cochin University of Science and Technology
Maria Starvin, A; Prasada Rao, T(CHEMICAL SCIENCES DIVISION REGIONAL RESEARCH LABORATORY (CSIR), July , 2007)
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Abstract:
Solid phase extraction (SPE) is a powerful technique for preconcentration/removal or separation of trace and ultra trace amounts of toxic and nutrient elements. SPE effectively simplifies the labour intensive sample preparation, increase its reliability and eliminate the clean up step by using more selective extraction procedures. The synthesis of sorbents with a simplified procedure and diminution of the risks of errors shows the interest in the areas of environmental monitoring, geochemical exploration, food, agricultural, pharmaceutical, biochemical industry and high purity metal designing, etc. There is no universal SPE method because the sample pretreatment depends strongly on the analytical demand. But there is always an increasing demand for more sensitive, selective, rapid and reliable analytical procedures. Among the various materials, chelate modified naphthalene, activated carbon and chelate functionalized highly cross linked polymers are most important. In the biological and environmental field, large numbers of samples are to be analysed within a short span of time. Hence, online flow injection methods are preferred as they allow extraction, separation, identification and quantification of many numbers of analytes. The flow injection online preconcentration flame AAS procedure developed allows the determination of as low as 0.1 µg/l of nickel in soil and cobalt in human hair samples. The developed procedure is precise and rapid and allows the analysis of 30 samples per hour with a loading time of 60 s. The online FI manifold used in the present study permits high sampling, loading rates and thus resulting in higher preconcentration/enrichment factors of -725 and 600 for cobalt and nickel respectively with a 1 min preconcentration time compared to conventional FAAS signal. These enrichment factors are far superior to hitherto developed on line preconcentration procedures for inorganics. The instrumentation adopted in the present study allows much simpler equipment and low maintenance costs compared to costlier ICP-AES or ICP-MS instruments.
Alex,Mathew; Dr.Madhusoodanan, K N(Cochin University of Science and Technology, June , 2004)
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Abstract:
The thesis provides an overall review and introduction to amorphous semiconductors, followed by a brief discussion on the important structural models proposed for chalcogenide glasses and their electrical, optional and thermal properties. It also gives a brief description of the Physics of thin films, ion implantation and Photothermal Deflection Spectroscopy. A brief description of the experimental setup of a photothermal deflection spectrometer and the details of the preparation and optical characterization of the thin film samples. It deals with the employment of the subgap optional absorption measurement by PDS to characterize the defects, amorphization and annealing behavior in silicon implanted with B+ ions and the profiles of ion range and vacancy distribution obtained by the TRIM simulation. It reports the results of all absorption measurements by PDS in nitrogen implanted thin film samples of Ge-Se and As-Se systems
Joseph, Lyjo K; Dr. Radhakrishnan, P; Dr.Nampoori,V P N(Cochin University of Science & Technology, November , 2009)
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Abstract:
Nondestructive photothermal methods as well as optical absorption and fluorescence spectroscopy are utilized to characterise three different materials, both thermally and optically. The possibility of using montmorillonite clay minerals, after textile waste-water treatment, is investigated for further applications. The laser induced luminescence studies and thermal characterisation of certain rare earth titanates prepared by self propagating high temperature synthesis method are also presented. Moreover, effort is made to characterise rare earth doped sol gel silica glasses with the help of these nondestructive techniques.
Description:
International School of Photonics, Cochin University of Science and Technology
Lyjo, Joseph K; Dr. Radhakrishnan, P(Cochin University of Science And Technology, November , 2009)
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Abstract:
The advent of high optical quality transparent nano—structured glasses, the so-called transparent glass ceramics or vitroceramics disclosed the possibility of producing nano-sized photonic devices based on rare-earth doped up—converters. Transparent glass ceramics have been investigated as hosts for lanthanide ions envisioning the production of materials that are easy to shape and with high performance for photonic applications. Rare earth doped glasses have been extensively studied due to their potential applications in optical devices such as solid state lasers and optical fibers. Various photothermal and optical techniques have been successfully applied for the thermal and optical characterization of these rare earth doped materials. In the present thesis, the effective thermal parameters like thermal diffusivity and thermal effusivity of complex materials for various applications have been investigated using photothermal methods along with their optical characterization utilising the common optical absorption as well as fluorescence spectroscopic techniques. These sensitive optical procedures are also essential for exploiting these materials for further photonic applications.
Description:
School of photonics, Cochin University of Science And Technology
Harilal, S S; Girijavallabhan, C P(Cochin University of Science and Technology, 1997)
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Abstract:
This thesis is entitled “OPTICAL EMISSION DIAGNOSTICS OF LASER PRODUCED PLASMA FROM GRAPHITE AND YBa2Cu3O7. The work presented in this thesis covers the experimental results on the plasma produced with moderately high power laser with irradiance range in between 10 GW cm 2 to 100 GW cm -2. The characterization of laser produced plasma from solid targets viz. graphite and high temperature superconducting material like YBa2Cu3O7 have been carried out. The fundamental frequency from a Q - switched Nd: YAG laser with 9 ns pulse
duration is used for the present studies. Various optical emission emission diagnostic techniques were employed for the the characterization of the LPP which include emission spectroscopy, time resolved studies, line broadening method etc. In order to understand the physical nature of the LPP like recombination, collisional excitation and the laser interaction with plasma, the time resolved studies offer the most logical approach
Jude Martin, Mendez; Dr.George, K E(Cochin University of Science & Technology, October , 2009)
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Abstract:
This study was undertaken in order to upgrade blends of HDPE and
PP, two of the most widely used standard plastics so as to widen their
application spectrum. Dicumyl peroxide was used as the modifier for the
upgradation. Optimum concentration of dicumyl peroxide required for
modification was detennined by measurement of mechanical, rheological,
thermal and morphological properties. Selected blends were used to prepare
recyclable composites with nylon clothes by compression moulding. The
composites were characterized by measurement of mechanical and thermal
properties. The composites were recycled and the mechanical propertics of
the recycled material were determined.
Description:
Dept.of Polymer Science and Rubber Technology,
Cochin University of Science and technology
Rinku Mariam, Thomas; Dr.George, K E; Dr.Mathew, K T; Dr.Prathapan, S(Cochin University of Science & Technology, May , 2005)
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Abstract:
The thesis deals with the preparation and dielectric characterization of
Poly aniline and its analogues in ISM band frequency of 2-4 GHz that includes part
of the microwave region (300 MHz to 300 GHz) of the electromagnetic spectrum
and an initial dielectric study in the high frequency [O.05MHz-13 MHz].
PolyaniIine has been synthesized by an in situ doping reaction under different
temperature and in the presence of inorganic dopants such as HCl H2S04, HN03,
HCl04 and organic dopants such as camphorsulphonic acid [CSA],
toluenesulphonic acid {TSA) and naphthalenesulphonic acid [NSA]. The variation
in dielectric properties with change in reaction temperature, dopants and
frequency has been studied. The effect of codopants and microemulsions on the dielectric properties has also been studied in the ISM band. The ISM band of
frequencies (2-4 GHz) is of great utility in Industrial, Scientific and Medical (ISM)
applications. Microwave heating is a very efficient method of heating dielectric
materials and is extensively used in industrial as well as household heating
applications.
Description:
Department of
Polymer Science and Rubber Technology,Cochin University of Science and
Technology
Vineetha, C P; Dr Babu, C.A(Cochin University of Science and Technology, June 22, 2015)
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Abstract:
The renewable energy sources (RES) will play a vital role in the
future power needs in view of the increasing demand of electrical
energy and depletion of fossil fuel with its environmental impact. The
main constraints of renewable energy (RE) generation are high capital
investment, fluctuation in generation and requirement of vast land area.
Distributed RE generation on roof top of buildings will overcome these
issues to some extent.
Any system will be feasible only if it is economically viable and
reliable. Economic viability depends on the availability of RE and
requirement of energy in specific locations. This work is directed to
examine the economic viability of the system at desired location and
demand.
Jomy, John; Dr.Pramod, K V(Cochin University of Science And Technology, January 30, 2014)
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Abstract:
The objective of the study is to develop a hand written character recognition system that could recognisze all the characters in the mordern script of malayalam language at a high recognition rate
Description:
Department of Computer Applications
Cochin University of Science and Technology
Suneesh, C V; Dr. Gopidas, K R(Cochin University of Science and Technology, May 3, 2010)
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Abstract:
This thesis Entitled phenylethynylarene based Donor-Acceptor systems:Desigh,Synthesis and Photophysical studies. A strategy for the design of donor-acceptor dyads, wherein decay of the charge separated (CS) state to low lying local triplet levels could possibly be prevented, is proposed. In order to examine this strategy, a linked donor-acceptor dyad BPEPPT with bis(phenylethYlly/)pyrene (BPEP) as the light absorber and acceptor and phenothiazine (PT) as donor was designed and photoinduced electron transfer in the dyad investigated. Absorption spectra of the dyad can be obtained by adding contributions due 10 the BPEP and PT moieties indicating that the constituents do not interact in the ground stale. Fluorescence of the BPEP moiety was efficiently quenched by the PT donor and this was attributed to electron lransfer from PT to BPEP. Picosecond transient absorption studies suggested formation of a charge separated state directly from the singlet excited state of BPEP. Nanosecond flash photolysis experiments gave long-ived transient absorptions assignable to PT radical cation and BPEP radical anion. These assignments were confirmed by oxygen quenching studies and secondary electron transfer experiments. Based on the available data, energy level diagram for BPEP-PT was constructed. The long lifetime of the charge separated state was attributed to the inverted region effects. The CS state did not undergo decay to low lying BPEP triplet indicating the success of our strategy
Description:
Photosciences and Pholonics
Chemical Sciences and Technology Division
Nibu, A George; Dr. Radhakrishnan, P(Cochin University of Science and Technology, May 14, 2001)
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Abstract:
The emergence of lasers in the early sixties has not only revolutionized the field of optics
and communication but also paved new ways in the field of material characterization. Material studies using photothermal techniques possess certain unique characteristics and advantages over conventional methods. The most important aspect of photothennal techniques is their ability to perform noncontact and nondestructive measurement. Photoacoustics, photothermal deflection, thermal lens, photothermal radiometry and photopyroelectric methods are some of the commonly used and powerful techniques for the thermal and optical characterization of materials using lasers.
In this thesis the applications of photoacoustic and photothermal deflection techniques
for the thermal and optical characterization of different photonic materials, namely,
semiconductors, liquid crystals and dye-doped polymers are discussed
Description:
International
School of Photonics, Cochin University of Science and Technology
Nithyaja, B; Dr.Nampoori,V P N(Cochin University of Science and Technology, January , 2012)
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Abstract:
This thesis Entitled Photonic applications of biomaterials with special reference to biopolymers and microbes. A detailed investigation will be presented in the present thesis related to direct applications of biopolymers into some selected area of photonics and how the growth kinetics of an aerial bacterial colony on solid agar media was studied using laser induced fluorescence technique.
This chapter is an overview of the spectrum of biomaterials and their application to Photonics. The chapter discusses a wide range of biomaterials based photonics applications like efficient harvesting of solar energy, lowthreshold lasing, high-density data storage, optical switching, filtering and template for nano s tructures. The most extensively investigated photonics application in biology is Laser induced fluorescence technique. The importance of fluorescence studies in different biological and related fields are also mentioned in this chapter.
Description:
International School of Photonics, Cochin University of Science and Technology
Antony, T P; Dr.Joseph,Francis D(Cochin University Of Science And Technology, December 4, 1989)
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Abstract:
The main objectives of the investigations
reported in the present thesis are the following: (1)
to find out some industrial wastes as cheaper additives
to augment the air-blowing polymerization process
of bitumen. This will bring down the cost of production
of industrial bitumen which can be applied for the
manufacture of bitumenous paints, roofing and flooring
materials etc. (2) to find out suitable promoters
for the above additives. This will bring down the
consumption of the additives (3) to help in the
industrial pollution control (4) to investigate the
usefulness of the industrial bitumen produced in the
production of bituminous paints (5) to find out thekinetic parameters of the reactions invovled with
different additives. This is essential for the design,
construction and operation of new industrial bitumen
plants using the additives investigated. This will
also enable us to establish the mechanism of the
reactions involved in the process
Description:
Department of Polymer Science and
Rubber Technology, Cochin University of Science and
Technology
Anoop Anand,K; Dr.Rani,Joseph(Cochin University of Science & Technology, December , 2006)
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Abstract:
The current research investigates the possibility of using single walled carbon
nanotubes (SWNTs) as filler in polymers to impart several properties to the matrix
polymer. SWNTs in a polymer matrix like poly(ethylene terephthalate) induce
nucleation in its melt crystallization, provide effective reinforcement and impart
electrical conductivity. We adopt a simple melt compounding technique for
incorporating the nanotubes into the polymer matrix. For attaining a better dispersion
of the filler, an ultrasound assisted dissolution-evaporation method has also been tried.
The resulting enhancement in the materials properties indicates an improved
disentanglement of the nanotube ropes, which in turn provides effective matrix-filler
interaction. PET-SWNT nanocomposite fibers prepared through melt spinning
followed by subsequent drawing are also found to have significantly higher mechanical
propertiesas compared to pristine PET fiber.SWNTs also find applications in composites based on elastomers such as natural
rubber as they can impart electrical conductivity with simultaneous improvement in the
mechanical properties.
Description:
Department of Polymer Science and Rubber Technology,
Cochin University of Science and Technology