Ashokakumaran, Unnithan K; Dr.Menon,N R; Dr.Kuttyamma, V J(Cochin University Of Science And Technology, August , 1997)
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Abstract:
The present research programme envisages a comparative study of the effects of
two piscicides of plant origin, viz., mahua oil cake, a derivative from the plant fig
Iatifolia and croton seed, a product from the plant Croton tiglium. Although some reports
on the effects of mahua oil cake and croton seed on fresh water pond culture systems are
available, information on their effect on brackishwater culture systems are rather scanty
This was the guiding principle for launching the present study It is hoped that the findings
will enable aquaculturists to make use of the piscicides in a more rational and efficient
way, and will go a long way towards realising the maximum return liom culture systems
without hampering the environment.
The thesis is presented in seven chapters such as Introduction, Review of
literature, Materials and Methods, Results, Discussion, Summary and Bibliography
Description:
School of Marine Sciences. Cochin University of Science and
Technology
Sebastian, Thomas; Dr.Meera Bai,M(Cochin University of Science And Technology, July , 2013)
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Abstract:
one of the key sectors, identified by the
Department of Industries Government of Kerala, for the cluster development
initiative is Handloom, which gives employment to over over 50,000 people
directly. Despite its age old tradition and fame, the performance of the sector
vis-à-vis power looms is not very rosy owing to (i) competition from cheap
power loom cloth from other states (ii) scarcity of quality yarn (iii) price
escalation of yarn, dyes, chemicals and other raw materials (iv) the shrinking
market for handlooms in Kerala (v) non-demand based production and
inadequacy of new designs and (vi) inefficiencies in the system, particularly in
the co-operative sector. Cluster based approach is adopted in the handloom
sector with the objective of providing necessary support mechanism to come out of the crisis that the sector faces now. While four cluster schemes are being
implemented in Kerala, it is under IHDS-CDP that the State got a sizeable
number of clusters benefiting a large number of societies and weavers- 24
handloom clusters, bringing 152 handloom co-operative societies and over
19,800 handloom workers under the Programme.
This research attempts to revisit the underlying rationale and context of
the new direction and would attempt to broadly analyze the growth trends under
the influence of cluster model adopted by the State IHDS-CDP for the revival
of handloom sector through a detailed study of the handloom co-operative
societies in Kerala. If handloom sector in Kerala can be revived using cluster
based approach, it can be easily concluded that cluster is capable of taking the
MSME in Kerala to a ‘high growth path.’ The study is aimed at understanding
how best clusters emerge as appropriate industrial organization suitable for the
current global structure of manufacture
Description:
Department of Applied Economics,Cochin University Of Science And Technology
Antony,M T; Jose,T Payyappilly(Department of Applied Economics, Faculty of Social Science, February , 1992)
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Abstract:
For the analysis of productivity, capacity utilisation
and profitability the data relating to the manufacturing central
public sector enterprises in Kerala have been collected from the
published annual reports of the companies, public enterprises
surveys of Bureau of Public Enterprises (BPE), Economic Review of
State Planning Board (SPB) and statistical review of central
government enterprises by Centre for Monitoring Indian Economy
(CMIE). Primary data have been collected by conducting personal
interview with the high and middle level executives.
Shahana, T K; Dr.Poulose Jacob, K; Dr.Sreela, Sasi(Cochin University of Science and Technology, October , 2008)
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Abstract:
The thesis focuses on efficient design methods and reconfiguration architectures suitable for higher performance wireless communication .The work presented in this thesis describes the development of compact,inexpensive and low power communication devices that are robust,testable and capable of handling multiple communication standards.A new multistandard Decimation Filter Design Toolbox is developed in MATLAB GUIDE environment.RNS based dual-mode decimation filters reconfigurable for WCDMA/WiMAX and WCDMA/WLANa standards are designed and implemented.It offers high speed operation with lesser area requirement and lower dynamic power dissipation.A novel sigma-delta based direct analog-to-residue converter that reduces the complexity of RNS conversion circuitry is presented.The performance of an OFDM communication system with a new RRNS-convolutional concatenated coding is analysed and improved BER performance is obtained under different channel conditions. Easily testable MAC units for filters are presented using Reed-Muller logic for realization.
Description:
Department of Computer Science,
Cochin University of Science and Technology
Remya, A R; Sreekumar, A(Cochin University of Science and Technology, June , 2014)
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Abstract:
Presently different audio watermarking methods are available; most of them
inclined towards copyright protection and copy protection. This is the key
motive for the notion to develop a speaker verification scheme that guar-
antees non-repudiation services and the thesis is its outcome.
The research presented in this thesis scrutinizes the field of audio water-
marking and the outcome is a speaker verification scheme that is proficient
in addressing issues allied to non-repudiation to a great extent. This work
aimed in developing novel audio watermarking schemes utilizing the fun-
damental ideas of Fast-Fourier Transform (FFT) or Fast Walsh-Hadamard
Transform (FWHT). The Mel-Frequency Cepstral Coefficients (MFCC) the
best parametric representation of the acoustic signals along with few other
key acoustic characteristics is employed in crafting of new schemes. The au-
dio watermark created is entirely dependent to the acoustic features, hence
named as FeatureMark and is crucial in this work.
In any watermarking scheme, the quality of the extracted watermark de-
pends exclusively on the pre-processing action and in this work framing and windowing techniques are involved. The theme non-repudiation provides
immense significance in the audio watermarking schemes proposed in this
work. Modification of the signal spectrum is achieved in a variety of ways
by selecting appropriate FFT/FWHT coefficients and the watermarking
schemes were evaluated for imperceptibility, robustness and capacity char-
acteristics. The proposed schemes are unequivocally effective in terms of
maintaining the sound quality, retrieving the embedded FeatureMark and
in terms of the capacity to hold the mark bits.
Robust nature of these marking schemes is achieved with the help of syn-
chronization codes such as Barker Code with FFT based FeatureMarking
scheme and Walsh Code with FWHT based FeatureMarking scheme. An-
other important feature associated with this scheme is the employment
of an encryption scheme towards the preparation of its FeatureMark that
scrambles the signal features that helps to keep the signal features unreve-
laed.
A comparative study with the existing watermarking schemes and the ex-
periments to evaluate imperceptibility, robustness and capacity tests guar-
antee that the proposed schemes can be baselined as efficient audio water-
marking schemes. The four new digital audio watermarking algorithms in
terms of their performance are remarkable thereby opening more opportu-
nities for further research.
Vimala,George; Jacob, Philip(Department of Electronics, October , 2005)
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Abstract:
The present work is an attempt to probe the elastic properties in some dielectric ceramics, by using ultrasonic pulse echo overlap technique. The base Ba6-xSm8+2xTi18O54 and Ca5Nb2TiO12 are very important dielectrics ceramics used for microwave communication as well as for substrate materials. Ultrasonic is one of the most widely used and powerful techniques to measure elastic properties of solids. The ultrasonic technique is nondestructive in nature and the measurements are relatively straightforward to perform. One unique advantantage of the ultrasonic technique is that both static and dynamic properties can be measured simultaneously. The velocity and attenuation coefficients of the ultrasonic waves propagating through a medium are related to the microscopic structure of the material and they provide valuable information about the structural changes in the system. Among the various ultrasonic techniques, the pulse echo overlap method is the most accurate and precise one. In the present case the decreased elastic properties of Cas-XMg,Nb2TiO12 and Cas-,ZnNb2TiO12 ceramics can be attributed to their mixture phases beyond x = 1. Moreover, the abrupt change in elastic properties observed for x >1 can also be correlated to the structural transformation of the materials from their phase pure form to mixture phases for higher extent of substitution of the concerned material . Ca4(ANb2Ti)012 (A = Mg, Zn) is the strongest compound with the maximum values for elastic properties . This could be due to the possible substitution of Mg/Zn ions with lesser radius [25] than Ca2+ in perovskite B-site of Ca(Cali4Nb2i4Tili4) O3 material to contribute more ordering and symmetry to the system [20]. All other compositions (x > 1) contain mixed-phases and for such mixed-phase samples, the mechanical properties are difficult to explain.
Rajeev, Kumar K; Dr.Sathianandan, K(Cochin University of Science and Technology, June 20, 1989)
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Abstract:
A brief account of the several methods used for the production of thin films is presented in this Chapter. The discussions stress on the important methods used for the fabrication of a-si:H thin films. This review' also reveals ‘that almost all the general methods, like vacuum evaporation, sputtering,
glow discharge and even chemical methods are currently employed for the production of a-Si:H thin films. Each method has its own advantages and disadvantages. However, certain methods are generally preferred. Subsequently a detailed account of the method used here for the preparation of amorphous silicon thin films and their hydrogenation is presented. The metal chamber used for the electrical and dielectric measurements is also described. A brief mention is made-on the electrode
structure, film area and film geometry.
Description:
Division of Thin Film, Department
of Physics, Cochin University of Science and Technology
Navil Kumar, R; Dr.Girijavallabhan,C P(Cochin University Of Science And Technology, June 28, 1989)
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Abstract:
In the present thesis a series of exhaustive
investigations have been carried out on a number of crystalline
samples with special reference tx> the jphase transitions
exhibited by them. These include single crystals
of pure, doped or deuterated specimens of certain ammonium
containing crystals viz., (NH )34H(SO4)2, (NH4)2HPO4,
(NH4)2Cr2O7 znui NH4H2PO4. ac/dc electrical conductivity,
dielectric constant, ionic thermocurrent as wwifil as photoacoustic
measurements have been carried out on most of
them over a wide range of temperature. In addition investigations
have been carried out in pure and doped single
crystals of NaClO3 and NaNO3 using ionic thermocurrent
measurements and these are presented here. Special attention
has been paid to reveal the mechanism of electrical conduction
in various phases of "these crystals and to evaluate
the different parameters involved in the conduction as well
as phase transition process.
The thesis contains ten chapters ‘
Description:
Department of Physics, Cochin
University of Science and Technology
Syamaprasad, U; Dr.Girijavallabhan,C P(Cochin University of Science And Technology, December , 1981)
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Abstract:
The thesis aims to present the results of the
experimental investigations on the electrical properties like
electrical conductivity, dielectric constant and ionic thermo~
currents in certain ammonium containing ferroelectric crystals
viz. LiNH4SO4, (NH4)2SO4 and (NH4)5H(SO4)2. Special attention
has been paid in revealing the mechanisms of electrical conduction
in the various phases of these crystals and those asso~
ciated with the different phase transitions occurring in them,
by making studies on doped, quenched and deuterated crystals.
The report on the observation of two new phase transitions in
(NH4) S O2 and of a similar one in ( NH4 ) H (2SO4 ) are included. The relaxation mechanisms of the impurity-vacancy complexes and the space charge phenomena in pure and doped crystals of LiNH4SO4 and (NH4)2SO4 and the observation of a new type of ionic thermo-current viz. Protonic Thermo-Current (PTC) in these crystals are also presented here.
Description:
Department of Physics, Cochin University of Science and Technology
Abraham,P K; Dr.Sathianandan, K(Cochin University of Science and Technology, July , 1989)
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Abstract:
This thesis Entitled Electrical switching studies on the thin flims of polyfuran and polyacrylonitrile prepared by plasma polymerisation and vacuum evaporated amorphous silicon.A general introduction to the switching and allied phenomena is presented. Subsequently, developments of switching in thin films are described. The Mott transition is qualitatively presented. The working of a switching transitor is outlined and compared to the switching observed in thin films. Characteristic parameters of switching such as threshold voltage, time response to a, voltage pulse, and delay time are described. The various switching configurations commonly used are discussed. The mechanisms used to explain the switching behaviour like thermal, electrothermal and purely electronic are reviewed. Finally the scope, feasibility and the importance of polymer thin films in switching are highlighted.
Description:
Department of Physics, Division of Thin Film, Cochin University of Science and Tecnology
Harikumar,P S; Dr.Sivasankara Pillai, V N(Cochin University of Science and Technology, 1990)
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Abstract:
The primary aim of these investigations was to probe the elecnuchemical
and material science aspects of some selected metal phthalocyanines(MPcs).Metal phthalocyanines are characterised by a unique planar molecular structure. As a single
class of compounds they have been the subject of ever increasing number of physicochemical and
technological investigations. During the last two decades the literature on these compounds was
flooded by an outpour of original publications and patents. Almost every branch of materials science
has benefited by their application-swface coating, printing, electrophotography, photoelectrochemistry,
electronics and medicine to name a few.The present study was confined to the electrical and electrochemical properties of cobalt,
nickel, zinc. iron and copper phthalocyanines. The use of soluble Pes as corrosion inhibitor for
aluminium was also investigated.In the introductory section of the thesis, the work done so far on MPcs is reviewed. In this
review emphasis is given to their general methods of synthesis and the physicochemical properties.In phthalocyanine chemistry one of the formidable tasks is the isolation of singular species.
In the second chapter the methods of synthesis and purification are presented with necessary
experimental details.The studies on plasma modified films of CoPe, FePc, ZnPc. NiPc and CuPc are also presented.Modification of electron transfer process by such films for reversible redox systems
is taken as the criterion to establish enhanced electrocatalytic activity.Metal phthalocyanines are p- type semiconductors and the conductivity is enhanced by
doping with iodine. The effect of doping on the activation energy of the conduction process is
evaluated by measuring the temperature dependent variation of conductivity. Effect of thennal
treatment on iodine doped CoPc is investigated by DSC,magnetic susceptibility, IR, ESR and
electronic spectra. The elecnucatalytic activity of such doped materials was probed by cyclic
voltammetry.The electron transfer mediation characteristics of MPc films depend on the film thickness.
The influence of reducing the effective thickness of the MPc film by dispersing it into a conductive
polymeric matrix was investigated. Tetrasulphonated cobalt phthalocyanine (CoTSP) was
electrostatically immobilised into polyaniline and poly(o-toluidine) under varied conditions.The studies on corrosion inhibition of aluminium by CoTSP and CuTSP and By virtue of their anionic character they are soluble in water and are strongly adsorbed on aluminium.
Hence they can act as corrosion inhibitors. CoTSP is also known to catalyze the reduction of
dioxygen.This reaction can accelerate the anodic dissolution of metal as a complementary reaction.
The influence of these conflicting properties of CoTSP on the corrosion of aluminium was studied
and compared with those of CuTSP.In the course of these investigations a number of gadgets like cell for measuring the electrical
conductivity of solids under non-isothermal conditions, low power rf oscillator and a rotating disc
electrode were fabricated.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology