Jaya, S; Dr. Ramakrishna, S V(Cochin University Of Science And Technology, August 19, 1999)
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Abstract:
P rosea syn. Indica belong to the family of plumbaginaceae, is an
important medicinal plant, cultivated widely in India. The roots of these
plant are generally used for medicinal purposes mainly as diuretic,
germicidal, vessicant, and abortifacient. It is also used for anaemia,
diarrhea, leprosy and common wart. The bark of the root contains orange
yellow pigment named plumbagin, a crystalline substance, belongs to the
class of naphthoquinone. Its chemical structure is 5-hydroxy 2-methyl 1,4naphthoquinone. Apart from P rosea, P zeylanica, P europea, Drosera
and Drosophyllum also contains plumbagin. The most exploited source of
plumbagin is, of course, P. rosea roots. The roots contain O.9mg/ g D.Wt. of
plumbagin in the roots. These plants grow very slowly and the roots suitable
for plumbagin extraction can be obtained only after several years of growth.
The productivity of the plant is also rather poor. The focus of the present study was to develop alternative strategies to obtain plumbagin. The tissue culture of P rosea for micropropagation has been studied
Description:
Department Of Biotechnology,Cochin University Of Science And Technology
Priya, Viswanath; Dr. Eby Thomas, Thachil(Cochin University of Science and Technology, September , 2007)
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Abstract:
Research in the field of polymer modified cement has been carried out for
the last 70 years or more. Polymers are mostly used to enhance durability and
sustainability of cement concrete and in combination with classical construction
materials a synergistic effect is obtained. In this work different polymers were
added to Portland cement in various proportions and the mechanical and
chemical resistance properties of the resultant composites when exposed to
chemical environments were studied. Microstructural studies were also carried
out to investigate the morphology of the composite and analyse the nature of
interactions taking place between the cement and polymer phases. Though most
polymers did not improve the compressive strength of the cement paste, it was
found that they enhanced the resistance of the virgin cement paste to external
chemical environments. The polymers seal the pores in the cement matrix and
bridge the microcracks within the composite. Some of the polymers underwent
chemical interactions with the cement paste thereby interfering in the hydration
of cement. Polymers also decreased the leachability of water soluble components
of virgin cement resulting in composites having improved durability. An attempt
to correlate the structure of the polymers with the properties of the resultant
composites is also presented.
Description:
Department of
Polymer Science and Rubber Technology, Cochin University of
Science and Technology
Jayalakshmy, M S; Jacob, Philip(Cochin University Of Science And Technology, May , 2015)
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Abstract:
The present work emphasises on the synthesis and characterization of electro-active polymer-ceramic nanocomposites which can be used for pyroelectric thermal/infrared detection applications. Two sets of samples belong to polymer-microcrystalline composites have also been investigated in the work. The polymers used in the work have been commercially available ones, but the nanoceramics have been synthesized following simple chemical routes and aqueous organic gel routes. After characterizing the nanoceramics for their structure by powder XRD, they have been dispersed in liquid polymer and sonicated for uniform dispersion. The viscous mixture so formed was cast in the form of films for experimentation. Samples with volume fraction of the ceramic phase varied from 0 to 0.25 have been prepared. Solution growth was followed to prepare microcrystalline samples for the polymer-microcrystalline composites. The physical properties that determine the pyroelectric sensitivity of a material are dielectric constant, dielectric loss, pyroelectric coefficient, thermal conductivity and specific heat capacity. These parameters have been determined for all the samples and compositions reported in this work.The pyroelectric figures of merit for all the samples were determined. The pyroelectric figures of merit that determine the pyroelectric sensitivity of a material are current sensitivity, voltage responsivity and detectivity. All these have been determined for each set of samples and reported in the thesis. In order to assess the flexibility and mouldability of the composites we have measured the Shore hardness of each of the composites by indentation technique and compared with the pyroelectric figures of merit. Some important factors considered during the material fabrication stages were maximum flexibility and maximum figures of merit for pyroelectric thermal/IR detection applications. In order to achieve these goals, all the samples are synthesized as composites of polymers and nano/microcrystalline particles and are prepared in the form of freestanding films. The selected polymer matrices and particle inclusions possess good pyroelectric coefficients, low thermal and dielectric properties, so that good
pyroelectric figures of merit could be achieved. The salient features of the work include the particle size of the selected ceramic materials. Since they are in nanometer size it was possible to achieve high flexibility and moldability with high figures of merit for even low volume fractions of inclusions of the prepared nanocrystalline composites. In the case of microcrystalline TGS and DTGS, their
composites in PU matrix protect them from fragility and humidity susceptibility and made them for environmental friendly applications.
Nisha, R; Dr.Madhusoodanan, K N(Cochin University of Science And Technology, March , 2013)
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Abstract:
One of the main challenges in the development of metal-oxide gas sensors
is enhancement of selectivity to a particular gas. Currently, two general
approaches exist for enhancing the selective properties of sensors. The first one
is aimed at preparing a material that is specifically sensitive to one compound
and has low or zero cross-sensitivity to other compounds that may be present in
the working atmosphere. To do this, the optimal temperature, doping elements,
and their concentrations are investigated. Nonetheless, it is usually very difficult
to achieve an absolutely selective metal oxide gas sensor in practice. Another
approach is based on the preparation of materials for discrimination between
several analyte in a mixture. It is impossible to do this by using one sensor
signal. Therefore, it is usually done either by modulation of sensor temperature
or by using sensor arrays.
The present work focus on the characterization of n-type semiconducting
metal oxides like Tungsten oxide (WO3), Zinc Oxide (ZnO) and Indium oxide
(In2O3) for the gas sensing purpose. For the purpose of gas sensing thick as well
as thin films were fabricated. Two different gases, NO2 and H2S gases were
selected in order to study the gas sensing behaviour of these metal oxides. To
study the problem associated with selectivity the metal oxides were doped with
metals and the gas sensing characteristics were investigated.
The present thesis is entitled “Development of semiconductor metal oxide
gas sensors for the detection of NO2 and H2S gases” and consists of six chapters.
Description:
Department of instrumentation, Cochin University of Science And Technology
Dinesh Kumar, V P; Dr. Tessamma, Thomas(Cochin University of Science and Technology, April , 2008)
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Abstract:
The wealth of information available freely on the web and medical image databases poses a major problem for the end users: how to find the information needed? Content –Based Image Retrieval is the obvious solution.A standard called MPEG-7 was evolved to address the interoperability issues of content-based search.The work presented in this thesis mainly concentrates on developing new shape descriptors and a framework for content – based retrieval of scoliosis images.New region-based and contour based shape descriptor is developed based on orthogonal Legendre polymomials.A novel system for indexing and retrieval of digital spine radiographs with scoliosis is presented.
Description:
Department of Electronics,
Cochin University of Science and Technology
Ananda Resmi, S; Dr. Tessamma, Thomas(Cochin University of Science And Technology, August 12, 2013)
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Abstract:
Cerebral glioma is the most prevalent primary brain tumor, which are
classified broadly into low and high grades according to the degree of malignancy.
High grade gliomas are highly malignant which possess a poor prognosis, and the
patients survive less than eighteen months after diagnosis. Low grade gliomas are
slow growing, least malignant and has better response to therapy. To date,
histological grading is used as the standard technique for diagnosis, treatment
planning and survival prediction.
The main objective of this thesis is to propose novel methods for automatic
extraction of low and high grade glioma and other brain tissues, grade detection
techniques for glioma using conventional magnetic resonance imaging (MRI)
modalities and 3D modelling of glioma from segmented tumor slices in order to
assess the growth rate of tumors. Two new methods are developed for extracting
tumor regions, of which the second method, named as Adaptive Gray level
Algebraic set Segmentation Algorithm (AGASA) can also extract white matter and
grey matter from T1 FLAIR an T2 weighted images. The methods were validated
with manual Ground truth images, which showed promising results. The developed
methods were compared with widely used Fuzzy c-means clustering technique and
the robustness of the algorithm with respect to noise is also checked for different
noise levels. Image texture can provide significant information on the
(ab)normality of tissue, and this thesis expands this idea to tumour texture grading
and detection. Based on the thresholds of discriminant first order and gray level cooccurrence
matrix based second order statistical features three feature sets were
formulated and a decision system was developed for grade detection of glioma
from conventional T2 weighted MRI modality.The quantitative performance
analysis using ROC curve showed 99.03% accuracy for distinguishing between
advanced (aggressive) and early stage (non-aggressive) malignant glioma. The
developed brain texture analysis techniques can improve the physician’s ability to
detect and analyse pathologies leading to a more reliable diagnosis and treatment of
disease. The segmented tumors were also used for volumetric modelling of tumors
which can provide an idea of the growth rate of tumor; this can be used for
assessing response to therapy and patient prognosis.
Description:
Department of Electronics
Cochin University of Science and Technology
Lakshmi,K; Dr.George, K E; Dr.Mathew, K T(Cochin University of Science & Technology, September , 2007)
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Abstract:
The microwave and electrical applications of some important conducting polymers are analyzed in this investigation.One of the major drawbacks of conducting polymers is their poor processability,and a solution to overcome this is sought in this investigation.Conducting polymer thermoplastic composites were prepared by the insitu polymerization method to improve the extent of miscibility probably to a semi IPN level.The attractive features of the conducting composite developed are excellent processability,good microwave and electrical conductivity,good microwave absorption,load sensitivity and satisfactory mechanical properties.The composite shows typical frequency selective microwave absorption and refelection behaviors.
Description:
Department of Polymer science and Rubber Technology ,Cochin University of Science and Technology
Roshen, Jacob; Dr.Unnikrishnan, A; Dr. Tessamma, Thomas(Naval Physical and Oceanographic Laboratory, November , 2010)
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Abstract:
Sonar signal processing comprises of a large number of signal processing algorithms
for implementing functions such as Target Detection, Localisation, Classification, Tracking
and Parameter estimation. Current implementations of these functions rely on conventional
techniques largely based on Fourier Techniques, primarily meant for stationary signals.
Interestingly enough, the signals received by the sonar sensors are often non-stationary and
hence processing methods capable of handling the non-stationarity will definitely fare better
than Fourier transform based methods.Time-frequency methods(TFMs) are known as one of the best DSP tools for nonstationary
signal processing, with which one can analyze signals in time and frequency
domains simultaneously. But, other than STFT, TFMs have been largely limited to academic
research because of the complexity of the algorithms and the limitations of computing power.
With the availability of fast processors, many applications of TFMs have been reported in the
fields of speech and image processing and biomedical applications, but not many in sonar
processing. A structured effort, to fill these lacunae by exploring the potential of TFMs in
sonar applications, is the net outcome of this thesis. To this end, four TFMs have been
explored in detail viz. Wavelet Transform, Fractional Fourier Transfonn, Wigner Ville
Distribution and Ambiguity Function and their potential in implementing five major sonar
functions has been demonstrated with very promising results. What has been conclusively
brought out in this thesis, is that there is no "one best TFM" for all applications, but there is
"one best TFM" for each application. Accordingly, the TFM has to be adapted and tailored
in many ways in order to develop specific algorithms for each of the applications.
Aysha, V; Dr.Kannan, B(Cochin University Of Science And Technology, June 30, 2013)
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Abstract:
The work is intended to study the following important aspects of
document image processing and develop new methods. (1) Segmentation ofdocument images using adaptive interval valued neuro-fuzzy method.
(2) Improving the segmentation procedure using Simulated Annealing
technique. (3) Development of optimized compression algorithms using
Genetic Algorithm and parallel Genetic Algorithm (4) Feature extraction of
document images (5) Development of IV fuzzy rules.
This work also helps for feature extraction and foreground and
background identification. The proposed work incorporates Evolutionary and
hybrid methods for segmentation and compression of document images. A
study of different neural networks used in image processing, the study of
developments in the area of fuzzy logic etc is carried out in this work
Description:
Dept of Computer Applications
Cochin University of Science and Technology
Roshni, Baby Thomas; Dr. Paulose, C S(Cochin University of Science And Technology, March 20, 2014)
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Abstract:
In the present work we studied the potential of Bacopa monnieri and Bacoside
A treatment to enhance the antioxidant system and support the neuronal survival
in the hypoglycemic neonatal brain. For achieving the aim, DAD1 and DAD2
receptors functional regulation, gene expression of growth factors, neuronal
survival and apoptotic factors during insulin induced hypoglycemic neonatal brain
in rats were studied.
Description:
Department of Biotechnology
Cochin University of Science and Technology
Joseph Francis,P J; Dr.Rani,Joseph(Cochin University of Science And Technology, April 20, 1998)
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Abstract:
Starve feeding of single screw extruder was described as an
important means of improving the performance characteristics of the
extruder. In addition to such improvement with versatility, the starve
feeding technique also may affect the mechanical properties of the
extrudate since the heat transfer an(l mixing characteristics in the starve
fed and Hood fed extruders are not the same. Since the material is more
loosely packed in the channels of the starve fed extruder, there may be
greater bed mobility and uniformity. Further, the. thermal an(l shear
induced degradation are also less since possibilities of developing local
high temperatures are less compared to a densely compacted extruder
bed. This study has been undertaken mainly to explore the effect of
feeding rate on the mechanical properties of rubber and plastic extrudates
since the effect of feeding rate has not been analysed from this angle so
far.
Description:
Department of Polymer
Science and Rubber Technology
Cochin University of
Science and Technology
Jose Sebastian; Dr. Eby Thomas Thachil(September 23, 2015)
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Abstract:
Organic-inorganic nanocomposites combine unique properties of
both the constituents in one material. Among this group of materials,
clay based as well as ZnO, TiO2 nanocomposites have been found to
have diverse applications. Optoelectronic devices require polymerinorganic
systems to meet certain desired properties. Dielectric
properties of conventional polymers like poly(ethylene-co-vinyl acetate)
(EVA) and polystyrene (PS) may also be tailor tuned with the
incorporation of inorganic fillers in very small amounts. Electrical
conductivity and surface resistivity of polymer matrices are found to
improve with inorganic nanofillers. II-VI semiconductors and their nano
materials have attracted material scientists because of their unique
optical properties of photoluminescence, UV photodetection and light
induced conductivity. Cadmium selenide (CdSe), zinc selenide (ZnSe)
and zinc oxide (ZnO) are some of the most promising members of the IIVI
semiconductor family, used in light-emitting diodes, nanosensors,
non-linear optical (NLO) absorption etc. EVA and PS materials were
selected as the matrices in the present study because they are
commercially used polymers and have not been the subject of research
for opto-electronic properties with semiconductor nanomaterials
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