Varghese,Joshua C; Krishnamoorthy,A(Department of Mathematics, 2003)
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Abstract:
Queueing system in which arriving customers who find all servers and waiting positions (if any) occupied many retry for service after a period of time are retrial queues or queues with repeated attempts. This study deals with two objectives one is to introduce orbital search in retrial queueing models which allows to minimize the idle time of the server. If the holding costs and cost of using the search of customers will be introduced, the results we obtained can be used for the optimal tuning of the parameters of the search mechanism. The second one is to provide insight of the link between the corresponding retrial queue and the classical queue. At the end we observe that when the search probability Pj = 1 for all j, the model reduces to the classical queue and when Pj = 0 for all j, the model becomes the retrial queue. It discusses the performance evaluation of single-server retrial queue. It was determined by using Poisson process. Then it discuss the structure of the busy period and its analysis interms of Laplace transforms and also provides a direct method of evaluation for the first and second moments of the busy period. Then it discusses the M/ PH/1 retrial queue with disaster to the unit in service and orbital search, and a multi-server retrial queueing model (MAP/M/c) with search of customers from the orbit. MAP is convenient tool to model both renewal and non-renewal arrivals. Finally the present model deals with back and forth movement between classical queue and retrial queue. In this model when orbit size increases, retrial rate also correspondingly increases thereby reducing the idle time of the server between services
Asha, A S; Dr.Jayaraj, M K(Cochin University of Science & Technology, December , 2007)
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Abstract:
The main objective of this thesis work is to optimize the growth conditions for
obtaining crystalline and conducting Lao.5Sro.5Co03 (LSCO) and
Lao.5Sro.5Coo.5.5Nio.5O3 (LSCNO) thin films at low processing temperatures. The
films are prepared by radio frequency magnetron sputtering under various
deposition conditions. The thin films were used as electrodes for the fabrication
of ferroelectric capacitors using BaO.7SrO.3 Ti03 (BST) and PbZro.52 Tio.4803 (PZT).
The structural and transport properties of the La1_xSrxCo03 and Lao.5Sro.5Co1_xNix03
are also investigated. The characterization of the bulk and the thin films were
performed using different tools. A powder X-ray diffractometer was used to
analyze the crystalline nature of the material. The transport properties were
investigated by measuring the temperature dependence of resistivity using a four
probe technique. The magnetoresistance and thermoelectric power were also used to investigate the transport properties. Atomic force microscope was used
to study the surface morphology and thin film roughness. The ferroelectric
properties of the capacitors were investigated using RT66A ferroelectric tester.
Description:
Department of Physics,
Cochin University of Science and Technology
Neema,C P; Dr.Babu, C A(Department of Atmospheric Science, 2004)
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Abstract:
This study deals with the salient features of the north Indian ocean associated with the summer monsoon. The focus is given on the Arabian sea mini warm pool, which is a part of the Indian ocean. It primarily study the certain aspects of the atmosphere and ocean variability in the north Indian ocean. The attempt were made to understand various aspects of time –scale variability of major features occurring in the Indian summer monsoon. The result from the thesis can be utilized as an input for model studies for prediction of monsoon, understanding ocean dynamics, radar tracking and ranging etc.
Haneesh Kumar,V; Samsuddin,M(Centre for Earth Science Studies, 2001)
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Abstract:
In the present investigation, an attempt is made to document various episodes of transgression and regression during the late Quaternary period from the study of coastal and shelf sequences extending from the inland across the beach to the shelf domain. Shore parallel beach ridges with alternating swales and occurrence of strand line deposits on the shelf make the northern Kerala coast an ideal natural laboratory for documenting the morpho-dynamic response of the coast to the changing sea level. The objectives of the study are lithographic reconstruction of environments of deposition from the coastal plain and shelf sequences; documentation of episodes of transgression and regression by studying different coastal plain sequences and shelf deposits and evolve a comprehensive picture of late Quaternary coastal evolution and sea level changes along the northern Kerala coast by collating morphological, lithological and geochronological evidences from the coastal plain and shelf sequences. The present study is confined to two shore-normal east-west trending transects, Viz. Punjavi and Onakkunnu, in the northern Kerala coast.
Navaneeth, P; Dr. Ramesh Babu, T; Dr. Robert K Plunkett(Cochin University of Science and Technology, July 11, 2016)
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Abstract:
Experimental Neutrino Physics is an active area of research in high energy
physics. The investigation of the properties of this elusive particles
has started since it’s discovery itself. In the standard model of particle
physics, neutrinos are massless, the discovery of neutrino oscillation is the
first evidence that demands the extensions of standard model. It is well
established the existence of three active neutrinos, e, μ and , but recent
experiments like LSND and MiniBooNE has found some anomalies
in their data. These experimental data could not be explained using three
flavour neutrino oscillation physics, but they could explain the anomaly
by adding a fourth type neutrino called sterile neutrinos. The evidences
obtained from these experiments are not yet conclusive. Search for sterile
neutrino is an extensive research area in the field of neutrino physics. The
main work presented in this thesis is a sterile neutrino search at MINOS
(Main Injector Neutrino Oscillation Search) experiment at Fermilab, USA.
MINOS is a two detector experiment at Fermilab, which studies the
neutrinos produced at Fermilab Main Injector particle accelerator. MINOS
Near Detector is situated at 1 km away from the source and the Far
Detector is at Soudan Mine at Minnesota, 735 km away from the neutrino
source. The experiment is built to study neutrino oscillation phenomena
in the atmospheric sector and has made world class measurements on neutrino
oscillation parameters. The MINOS experiment is also capable of
looking for small perturbation in the energy spectra caused by any fourth
type of neutrino and can extract the oscillation parameters.
Rajith,K; Kurian,N P(CENTRE FOR EARTH SCIENCE STUDIES, November , 2006)
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Abstract:
The Sediment budgeting studies are done to bring out the coastal processes at work, to understand the beach-innershelf sedimentary dynamics and to assess the stability of any coastal stretch. There is a dearth of such studies as far as the Indian coast is concerned. The Chavara coast of Kollam district, Kerala, is world famous for its rich heavy mineral resources. These mineral resources are being commercially mined by the Indian Rare Earths Ltd. (IREL) and Kerala Minerals and Metals Ltd. (KMML), two Public Sector Undertakings located in the area. The impact of mining on stability of the beach has been a point of debate among the local people as well as researchers. The coastal stretch of 22km length from Neendakara to Kayamkulam which is referred to as the Chavara coast. The tidal, wind driven and continental shelf currents, there could also be the contribution of coastal trapped waves and baroclinic flow associated with the plumes of fresh water coming from the estuaries. The main objectives of the study are the hydrodynamic processes and mechanism involved in the sediment movement along the Chavara coast, Identify the different sources and sinks of beach sand along the coast, Quantify the sediment input/output into/from the coast and assess the erosion/accretion scenario of the coast.
Manoj, E; Dr.Prathapachandra Kurup,M R(Cochin University of Science and Technology, October , 2007)
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Abstract:
Chemistry occupies a unique middle position in the scientific arena, between
physics and mathematics on the one side and biology, ecology, sociology and
economics on the other [1]. Chemistry is the science of matter and of its
transformations, and life is its highest expression [2]. According to reductionist
thinking biology is reducible into chemistry, chemistry into physics, and ultimately
physics into mathematics. Reductionism implies the ease of understanding one level
in terms of another.The work presented this thesis comprises synthesis and characterization of
suitably substituted thiocarbohydrazone and carbohydrazone ligand building blocks, self-assembled metallosupramolecular square grid complexes as well as some di/multinuclear complexes.
The primary aim was the deliberate syntheses of some novel transition metal framework
complexes, mainly metallosupramolecular coordination square grids by self-assembly
and their physico-chemical characterization. The work presented, however, also
include synthesis and characterization of four mononuclear Ni(II) complexes of two
thiosemicarbazones, which we carried out as a preliminary and supporting study. Based on the present work we would like to conclude that the carbohydrazones, thiocarbohydrazones and their coordination framework complexes of transition metals are promising systems for wide application in science and technology varied from physics to biotechnology. Novel classes of materials and biologically important potential compounds
open up further scope of researches and we hopefully welcome any sort of related research to make this work more valuable.
Korah, Kuruvilla P; Dr. Paulose, C S(Cochin University of Science and Technology, May 23, 2012)
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Abstract:
Parkinson’s disease is a chronic progressive neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in the SNpc resulting in severe motor impairments. Serotonergic system plays an important regulatory role in the pathophysiology of PD in rats, the evaluation of which provides valuable insight on the underlying mechanisms of motor, cognitive and memory deficits in PD. We observed a decrease in 5-HT content in the brain regions of 6-OHDA infused rat compared to control. The decreased 5-HT content resulted in a decrease of total 5-HT, 5-HT2A receptors and 5-HTT function and an increase of 5-HT2C receptor function. 5-HT receptor subtypes - 5-HT2A and 5-HT2C receptors have differential regulatory role on the modulation of DA neurotransmission in different brain regions during PD. Our observation of impaired serotonergic neurotransmission in SNpc, corpus striatum, cerebral cortex, hippocampus, cerebellum and brain stem demonstrate that although PD primarily results from neurodegeneration in the SNpc, the associated neurochemical changes in other areas of the brain significantly contributes to the different motor and non motor symptoms of PD. The antioxidant enzymes – SOD, CAT and GPx showed significant down regulation which indicates increased oxidative damage resulting in neurodegeneration. We also observed an increase in the level of lipid peroxidation. Reduced expression of anti-apoptotic Akt and enhanced expression of NF-B resulting from oxidative stress caused an activation of caspase-8 thus leading the cells to neurodegeneration by apoptosis. BMC administration in combination with 5-HT and GABA to PD rats showed reversal of the impaired serotonergic neurotransmission and oxidative stress mediated apoptosis. The transplanted BMC expressed NeuN confirming that 5-HT and GABA induced the differentiation and proliferation of BMC to neurons in the SNpc along with an increase in DA content and an enhanced expression of TH. Neurotrophic factors – BDNF and GDNF rendered neuroprotective effects accompanied by improvement in behavioural deficits indicating a significant reversal of altered dopaminergic and serotonergic neurotransmission in PD. The restorative and neuroprotective effects of BMC in combination with 5-HT and GABA are of immense therapeutic significance in the clinical management of PD.
Description:
Department of Biotechnology, Cochin University
of Science and Technology,
Digna, Varghese; Dr.Mohammed Yusuff,K K; Dr.Unnikrishnan, P A(Cochin University of Science & Technology, August , 2011)
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Abstract:
This thesis is mainly concerned with the synthesis and characterisation of new simple and zeolite encapsulated transition metal (manganese(II),nickel(II),and copper(II)complexes of quinoxaline based double Schiff base ligands.Theses ligands are N,N'-bis(quinoxaline-2-carboxalidene)hydrazine,N,N'-bis(quinoxaline-2-carboxalidene)-1,2-diaminoethane,N,N'-bis(quinoxaline-2-carboxalidene)-1,3-diamonopropane,N,N'-bis(quinoxaline-2-carboxalidene)-1,4-diaminobutane,N,N'-bis(quinoxaline-2-carboxalidene)-1,2-diaminocyclohexane and N,N'-bis(quinoxaline-2-carboxalidene)-1,2-diaminobenzene.The Schiff base ligands have been characterised by spectral and single crystal XRD studies.Theses ligands provide great structural diversity during complexation.Mn(II) and Ni(II) form octahedral with these Schiff bases,whereas Cu(II) forms both octahedral and tetrahedral complexes.Studies on the biological and Catalytic activity of the copper(ll) complexes are also presented in this thesis.
Description:
Dept.of Applied Chemistry,Cochin University of Science and Technology
Jayasankar, M; Dr.Warrier, K G K(National Institute for Interdisciplinary Science and Technology, December , 2009)
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Abstract:
The thesis entitled "Sol-Gel Alumina Nano Composites for
Functional Applications" investigate sol-gel methods of synthesis of alumina
nanocomposites special reference to alumina-aluminium titanate and alumina-lanthanum
phosphate composites. The functional properties such as thermal
expansion coefficient and thermal shock resistance, machinability of composites as well as thermal protection are highlighted in addition to novel
approach in synthesis of composites.A general introduction of alumina matrix composites materials,
followed by brief coverage of alumina-aluminium titanate and alumina-lanthanum
phosphate composites is highlight of the first chapter. The second
chapter deals with the sol-gel synthesis of aluminium titanate and alumina-aluminium
titanate composite. The synthesis of machinable substrate, based on
alumina and lanthanum phosphate forms the basis of the third chapter. The
fourth chapter describes the sol-gel coating of mullite on SiC substrate for the
possible gas filtration application.
Sankar, Sasidharan; Dr K.G.K Warrier(Cochin University of Science and Technology, January 16, 2015)
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Abstract:
Lanthanum phosphate is one among the lanthanide family of “Rare Earths” following the periodic table of elements. Known under the generic name, Monazite, the rare earth phosphates have melting points above 1900 °C, high thermal phase stability, low thermal conductivity and thermal expansion coefficient similar to some of the high temperature oxides like alumina and zirconia.
Smitha, Sasidharan; Dr.Warrier, K G K(Cochin University of Science & Technology, July , 2009)
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Abstract:
The thesis covers a systematic investigation on the synthesis of
silica aerogels and microspheres with tailored porosity, at ambient conditions by
varying the experimental parameters as well as using organic templates.
Organically modified silica-gelatin and silica-chitosan hybrids were developed for
the first time using alkylalkoxysilanes such as MTMS and VTMS. Application of
novel silica-biopolymer antiwetting coatings on different substrates such as glass,
leather and textile is also demonstrated in the thesis.
Sibu,C P; K G K Warrier(CSIR, FACULTY OF SCIENCE, 2004)
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Abstract:
In the present work Titania bulk powders and coatings were prepared by subjecting titanium isopropoxide solution to a controlled hydrolysis-condensation process. The powders were characterized using techniques such as FTIR for their chemical interactions, TG-DTA for the thermal decomposition features, XRD for the phase assemblage, BET specific surface area analysis for the textural features. The study discusses the preparation methods and the characterization techniques employed and a detailed discussion on the physico-chemical characterization of the prepared systems. The influence of dopants and leaching on the physico-chemical properties as well as their influence on photo activity is also included. The structural/functional coatings of different Titania compositions includes in this study. Coatings on pre-treated glass surfaces with the best compositions prepared showed 90 % transmittance in the visible region.