Sunny, Kuriakose; Dr.Abdul Rasheed, T M(Cochin University Of Science And Technology, October 7, 2003)
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Abstract:
Vibrational overtone spectroscopy of molecules containing X-H oscillators
(X = C, N, O...) has become an effective tool for the study of molecular structure,
dynamics, inter and intramolecular interactions, conformational aspects and
substituent effects in aliphatic and aromatic compounds. In the present work, the author studied the NIR overtone spectra of some liquid phase organic compounds. The analysis of the CH, NH and OH overtones yielded important structural
information about these systems. In an attempt to get information on electronic
energy levels, we studied the pulsed Nd:YAG laser induced fluorescence spectra
of certain organic compounds. The pulsed laser Raman spectra of some organic
compounds are also studied. The novel high resolution technique of near infrared
tunable diode laser absorption spectroscopy (TDLAS) is used to record the
rotational structure of the second OH overtone spectrum of 2-propanol. The
spectral features corresponding to the different molecular conformations could be
identified from the high resolution spectrum.
The whole work described in this thesis is divided into five chapters.
Description:
Department of Physics
Cochin University of Science and Technology
Kumar, G A; Gin, Jose; Vinoy, Thomas; Unnikrishnan, N V; Nampoori, V P N(Elsevier, 2003)
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Abstract:
Optical absorption studies of phthalocyanines (Pc-s) in borate glass matrix have been reported for the first time. Measurements have been done corresponding to photon energies between 1.1 and 6.2 eV for free base, manganese, iron, nickel, molybdenum, cobalt and copper phthalocyanines. Several new discrete transitions are observed in the UV–vis region of the spectra in addition to a strong continuum component of absorption in the IR region. Values of some of the important optical constants viz. absorption coefficient (α), molar extinction coefficient (ε), absorption cross-section (σa), band width (Δλ), electric dipole strength (q2) and oscillator strength (f) for the relevant electronic transitions are also presented. All the data reported for Pc-s in the new matrix have been compared with those corresponding to solution, vapor and thin film media.
Bright Singh, I S; Rosamma, Philip; Rejish Kumar, V J; Valsamma, Joseph; Vijai, R(Wiley, March 3, 2011)
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Abstract:
BACKGROUND: A packed bed bioreactor (PBBR) activated with an indigenous nitrifying bacterial consortia was developed
and commercialized for rapid establishment of nitrification in brackish water and marine hatchery systems in the tropics.
The present study evaluated nitrification in PBBR integrated into a Penaeus monodon recirculating maturation system under
different substrate concentrations and flow rates.
RESULTS:Instantnitrificationwasobservedafter integration ofPBBRinto thematuration system.TANandNO2-Nconcentrations
were always maintained below0.5 mg L−1 during operation. The TANandNO2-N removalwas significant (P < 0.001) in all the six
reactor compartments of the PBBR having the substrates at initial concentrations of 2, 5 and 10 mg L−1. The average volumetric
TAN removal rates increased with flow rates from 43.51 (250 L h−1) to 130.44 (2500 L h−1) gTAN m−3 day−1 (P < 0.05). FISH
analysis of the biofilms after 70 days of operation gave positive results with probes NSO 190 ((β ammonia oxidizers), NsV 443
(Nitrosospira spp.) NEU (halophilic Nitrosomonas), Ntspa 712 (Phylum Nitrospira) indicating stability of the consortia.
CONCLUSION: The PBBR integrated into the P. monodon maturation system exhibited significant nitrification upon operation
for 70 days as well as at different substrate concentrations and flow rates. This system can easily be integrated into marine and
brackish water aquaculture systems, to establish instantaneous nitrification
Sudha Kartha, C; Dr.Sathianandan, K(Cochin University of Science and Technology, February , 1984)
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Abstract:
The present study is mainly concéntrated on the visible
fluorescence of Ho3+ ,nd 3+ and Er 3+rare earths in
alkaline earth fluoride hosts(caF2,srF2,BaF2)
using a nitrogen laser excitation. A nitrogen laser was fabricated and its parametric studies were first carried out.
Description:
Department of Physics, Cochin University of Science and Technology
Mohammed Yusuff, K K; Digna, Varghese; Arun, Vasudevan; Manju, Sebastian; Leeju, P; Varsha, Gopalakrishnan(Crystallography Journals,Acta Crystallographica Section E ,Structure Reports, January 23, 2009)
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Abstract:
In the molecule of the title compound, C20H16N6, the central
C—C bond lies on a crystallographic inversion centre. The
quinoxalidine ring is nearly planar, with a maximum deviation
of 0.021 (2) A ˚ from the mean plane. The crystal structure is
stabilized by intermolecular C—H....N interactions, leading to
the formation of a layer-like structure, which extends along the
a axis
Sudha Kartha, C; Vijayakumar, K P; Tina, Sebastian; Deepa, K G; Anita, Warrier R(Elsevier, September 19, 2009)
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Abstract:
Photothermal deflection technique (PTD) is a non-destructive tool for measuring the temperature distribution
in and around a sample, due to various non-radiative decay processes occurring within the material. This tool
was used to measure the carrier transport properties of CuInS2 and CuInSe2 thin films. Films with thickness
<1 μm were prepared with different Cu/In ratios to vary the electrical properties. The surface recombination
velocity was least for Cu-rich films (5×105 cm/s for CuInS2, 1×103 cm/s for CuInSe2), while stoichiometric
films exhibited high mobility (0.6 cm2/V s for CuInS2, 32 cm2/V s for CuInSe2) and high minority carrier lifetime
(0.35 μs for CuInS2, 12 μs for CuInSe2
Paulraj,M; Dr.Vijayakumar, K P(Department of Physics, Faculty of Science, December , 2004)
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Abstract:
Materials and equipment which fail to achieve the design requirements or projected life due to undetected defects may require expensive repair or early replacement. Such defects may also be the cause of unsafe conditions or catastrophic unexpected failure, and will lead to loss of revenue due to plant shutdown. Non-Destructive Evaluation (NDE) / Non Destructive Testing (NDT) is used for the examination of materials and components without changing or destroying their usefulness. NDT can be applied to each stage of a system’s construction, to monitor the integrity of the system or structure throughout its life.
Poornima,N; Dr.Sudha Kartha,C(Cochin University Of Science And Technology, November , 2013)
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Abstract:
Photoluminescence (PL) spectroscopy is an optical technique that has
emerged successful in the field of semiconductor material and device
characterization. This technique is quite a powerful one which gives idea about
the defect levels in a material, the band gap of the material, composition as well
as material quality. Over the recent years it has received an elevation as a
mainstream characterization technique.
This thesis is an attempt to characterize each individual layer used in a thin
film solar cell with special focus on the electrical properties. This will be highly
beneficial from the lab as well as industrial point of view because electrical
measurements generally are contact mode measurements which tend to damage
the surface. As far as a thin film solar cell is concerned, the constituent layers are
the transparent conducting oxide (TCO), absorber layer, buffer layer and top
electrode contact. Each layer has a specific role to play and the performance of a
solar cell is decided and limited by the quality of each individual layer. Various
aspects of PL spectroscopy have been employed for studying compound
semiconductor thin films [deposited using chemical spray pyrolysis (CSP)]
proposed for solar cell application. This thesis has been structured in to seven
chapters
Description:
Applied Optics Division,
Department of Physics,
Cochin University of Science and Technology
Venugopalan, P; Dr.Nair, K G(Cochin University of Science and Technology, August , 1991)
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Abstract:
The motivatitni for" the present work is from .a
project sanctioned by TSRO. The work involved the development
of a quick and reliable test procedure using
microwaves, for tflue inspection of cured propellant samples
and a method to monitor the curing conditions of propellant
mix undergoing the curing process.Normal testing CHE the propellant samples involvecuttimg a piece from each carton and testing it for their tensile strength. The values are then compared with standard ones and based on this result the sample isaccepted or rejected. The tensile strength is a measure ofdegree of cure of the propellant mix. But this measurementis a destructive procedure as it involves cutting of the sample. Moreover, it does not guarantee against nonuniform curing due to power failure, hot air-line failure,operator error etc. This necessitated the need for the development of a quick and reliable non-destructive test
procedure.
Description:
Department of Electronics, Cochin University of Science and Technology
Radhakrishnan, P; Jayasree, V K; Sandhya, T V(Measurement Science Review, 2008)
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Abstract:
A non-invasive technique is implemented to measure a parameter which is closely related to the distensibility of large arteries,
using the second derivative of the infrared photoplethysmographic waveform. Thirty subjects within the age group of 20-61 years
were involved in this pilot study. Two new parameters, namely the area of the photoplethysmographic waveform under the systolic
peak, and the ratio of the time delay between the systolic and the diastolic peaks and the time period of the waveform (T/T) were
studied as a function of age. It was found that while the parameter which is supposed to be a marker of distensibility of large arteries
and T /T values correlate negatively with age, the area under the systolic peak correlates positively with age. The results suggest that
the derived parameters could provide a simple, non-invasive means for studying the changes in the elastic properties of the vascular
system as a function of age.
Lalaja, Varghese; Nampoori, V P N; Pratap, R(Current Science, October 20, 1987)
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Abstract:
A mathematical analysis of an electroencephalogram of a human Brain during an epileptic
seizure shows that the K2 entropy decreases as compared to a clinically normal brain while the
dimension of the attractor does not show significant deviation.
This study reports the details of the finite element analysis of eleven shear critical partially prestressed
concrete T-beams having steel fibers over partial or full depth. Prestressed T-beams having a shear span to
depth ratio of 2.65 and 1.59 that failed in shear have been analyzed using the ‘ANSYS’ program. The
‘ANSYS’ model accounts for the nonlinearity, such as, bond-slip of longitudinal reinforcement, postcracking
tensile stiffness of the concrete, stress transfer across the cracked blocks of the concrete and load
sustenance through the bridging action of steel fibers at crack interface. The concrete is modeled using
‘SOLID65’- eight-node brick element, which is capable of simulating the cracking and crushing behavior
of brittle materials. The reinforcement such as deformed bars, prestressing wires and steel fibers have been
modeled discretely using ‘LINK8’ – 3D spar element. The slip between the reinforcement (rebars, fibers)
and the concrete has been modeled using a ‘COMBIN39’- nonlinear spring element connecting the nodes
of the ‘LINK8’ element representing the reinforcement and nodes of the ‘SOLID65’ elements representing
the concrete. The ‘ANSYS’ model correctly predicted the diagonal tension failure and shear compression
failure of prestressed concrete beams observed in the experiment. The capability of the model to capture the
critical crack regions, loads and deflections for various types of shear failures in prestressed concrete beam
has been illustrated.
Anantharaman, M R; Reena Mary, A P; Suchand Sandeep, C S; Narayanan, T N; Reji, Philip; Padraig, Moloney; Ajayan, P M(IOP Publishing LTD, August 19, 2011)
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Abstract:
Oxide free stable metallic nanofluids have the potential for various applications such as in
thermal management and inkjet printing apart from being a candidate system for fundamental
studies. A stable suspension of nickel nanoparticles of ∼5 nm size has been realized by a
modified two-step synthesis route. Structural characterization by x-ray diffraction and
transmission electron microscopy shows that the nanoparticles are metallic and are phase pure.
The nanoparticles exhibited superparamagnetic properties. The magneto-optical transmission
properties of the nickel nanofluid (Ni-F) were investigated by linear optical dichroism
measurements. The magnetic field dependent light transmission studies exhibited a polarization
dependent optical absorption, known as optical dichroism, indicating that the nanoparticles
suspended in the fluid are non-interacting and superparamagnetic in nature. The nonlinear
optical limiting properties of Ni-F under high input optical fluence were then analyzed by an
open aperture z-scan technique. The Ni-F exhibits a saturable absorption at moderate laser
intensities while effective two-photon absorption is evident at higher intensities. The Ni-F
appears to be a unique material for various optical devices such as field modulated gratings and
optical switches which can be controlled by an external magnetic field