Sebastian, Mathew; Joe, Jacob; Joseph, V P; Bijukumar, S; Raveendranath, U; Mathew, K T(John Wiley & Sons, March 5, 1999)
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Abstract:
This paper presents the design of a new type of corner reflector (CR) antenna and the experimental investigation of its radiation characteristics. The design involves the addition of planar parallel periodic strips to the two sides of a CR antenna. The position, angular orientation, and number of strips have a notable effect on the H-plane radiation characteristics of the antenna. Certain configurations of the new antenna are capable of producing very sharp axial beams with gain on the order of 5 dB over the square corner reflector antenna. A configuration that can provide symmetric twin beams with enhanced gain and reduced half-power beam width (HPBW) is also presented.
New dielectric ceramics with formula BaTi3Nb4, O„ and Ba6Til4Nbz039 have been prepared and characterized. BaTi3Nba017 was densified to 92% of TD after firing at 1310 oC for 4 h. However, Ba6Ti 1 4Nb2O39 fired under optimized conditions (1260 ` C for 4 h) showed only 85% TD together with secondary phase. The crystal system of both of the compositions is orthorhombic
Pramitha, V; Dr.Sudha Kartha, C(Cochin University of Science and Technology, November , 2010)
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Abstract:
This thesis has discussed the development of a new metal ion doped
panchromatic photopolymer for various holographic applications. High-quality
panchromatic holographic recording material with high diffraction efficiency, high
photosensitivity and high spatial resolution is one of the key factors for the successful
recording of true colour holograms. The capability of the developed material for multicolour
holography can be investigated.In the present work, multiplexing studies were carried out using He-Ne laser
(632.8 nm). Multiplexing can be done using low wavelength lasers like Ar+ ion (488 nm)
and frequency doubled Nd: YAG (532 nm) lasers, so as to increase the storage capacity.
The photopolymer film studied had a thickness of only 130 Cm. Films with high
thickness (~500 Cm) is highly essential for competitive holographic memories .
Hence films with high thickness can be fabricated and efforts can be made to record
more holograms or gratings in the material.In the present study, attempts were made to record data page in silver doped
MBPVA/AA photopolymer film. Image of a checkerboard pattern was recorded in the
film, which could be reconstructed with good image fidelity. Efforts can be made to
determine the bit error rate (BER) which provides a quantitative measure of the image quality of the reconstructed image . Multiple holographic data pages can also be
recorded in the material making use of different multiplexing techniques.Holographic optical elements (HOEs) are widely used in optical sensors, optical
information processing, fibre optics, optical scanners and solar concentrators . The
suitability of the developed film for recording holographic optical elements like lenses,
beam splitters and filters can be studied.The suitability of a reflection hologram recorded in acrylamide based
photopolymer for visual indication of environmental humidity is reported . Studies
can be done to optimize the film composition for recording of reflection holograms.An improvement in the spatial resolution of PVA/acrylamide based
photopolymer by using a low molecular-weight poly (vinyl alcohol) binder was recently
reported . Effect of the molecular weight of the binder matrix on the holographic
properties of the developed photopolymer system can be investigated.Incorporation of nanoparticles into photopolymer system is reported to
enhance the resolution and improve the dimensional stability of the system .
Hence efforts can be made to incorporate silver nanoparticles into the photopolymer
and its influence on the holographic properties can be studied.This thesis was a small venture towards the realization of a big goal, a
competent holographic recording material with excellent properties for practical
holographic applications. As a result of the present research, we could successfully
develop an efficient panchromatic photopolymer system and could demonstrate its
suitability for recording transmission holograms and holographic data page. The
developed photopolymer system is expected to have significant applications in the
fields of true-color display holography, wavelength multiplexing holographic storage,
and holographic optical elements. Highly concentrated and determined effort has yet to
be put forth for this expectation to become a reality.
Description:
Department of Physics,
Cochin University of Science and Technology
Monz, Cabrera J; Diaz, Morcillo A; Pedreno, Molina L; Sanchez, Hermandez D(Microwave and Optical Technology Letters, February 4, 2004)
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Abstract:
Usage of a dielectric multilayer around a dielectric Sample
is studied as a means for improving the efficiency in multimode microwave-
heating cavities. The results show that by using additional dielectric
constant layers the appearance of undesired reflections at the
sample-air interface is avoided and higher power -absorption rates
within the sample and high -efficiency designs are obtained
Binu,Paul; Mridula,S; Aanandan,C K; Mohanan,P(Microwave Engineering Group,Department of Electronics, May 20, 2002)
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Abstract:
compact multihand planar octagonal-shaped microstrip
antenna simultaneously suitable for mobile communication and blue
tooth application is presented. The antenna provides sufficient isolation
benveen the two operating bands and an area reduction of -29 % with
respect to a circular patch operating in the same band
New oligomer-bound antioxidants have been prepared by condensation reaction. The efficiency and permanence of these oligomer-
bound paraphenylene diamines as antioxidants has been compared with conventional amine type antioxidants in NR, SBR,
IIR and NBR and in elastomer blends like NR/BR and NR/SBR. The oligomer-bound antioxidants are found to impart improved
ozone, flex resistance and mechanical properties to the vulcanizates of NR, SBR, IIR and NBR and to blends of NR/BR and NR/
SBR in comparison with those containing conventional antioxidants.
Stephen,D S; Mathew,T; Jose,K A; Aanandan,C K; Mohanan,P; K G Nair(Department of Electronics, February , 1993)
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Abstract:
Simultaneous elimination of specular reflection and backscattered
power from a plane metallic surface by simulated
corrugated surfaces of constant period and variable strip
width for TM polarisation is reported. This new configuration
offers almost a ten-fold frequency bandwidth compared
with a regularly spaced strip grating of the same size.
N R Menon; Priyalakshmi, G; Antonio Todaro, M(Zootaxa, October 17, 2007)
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Abstract:
During an interstitial faunal survey along the south-west coast of Kerala, India, gastrotrich fauna were found in abundance.
Together with species of the genera Xenotrichula, Halichaetonotus and Tetranchyroderma, were present several
undescribed thaumastodermatid gastrotrichs belonging to the buccal palp bearing genus Pseudostomella. Adults of the
new species are characterized by the following traits: total body length of about 300 μm; cuticular armature made up of
medium sized pentancres covering the entire dorsolateral surface; pre-buccal, grasping palps bearing five, large papillae
dorsally and 4-6 smaller papillae ventrally; adhesive apparatus made up of six anterior, 22-24 ventrolateral, two dorsolateral
and six posterior adhesive tubes; caudal organ pear-shaped; frontal organ spherical. Pseudostomella cheraensis sp.
nov. is the fourth taxon of the genus known from India; however, all the previous species reported hitherto from India
have tetrancres instead of pentancres.
Girish Kumar, K; Chowdary, K P R; Devala Rao, G(Indian Journal Of Pharmaceutical Sciences, January 8, 1999)
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Abstract:
Two simple and sensitive spectrophotometric methods (A and B)in the visible region have been developed for the determination of nimesulide in bulk and in dosage forms.Method A is based on the reaction of reduced nimesulide with nitrous acid followed by its coupling with phloroglucinol to yield an yellow colored azo dye with an absorption maximum of 400 nm and method B is based on the reaction of reduced nimesulide with p-dimethylamino benzaldehyde(PDAB) to form an yellow colored chromogen wiht an absorption maximum of 415 nm.When pharmaceutical preparations (Tablets and suspension) were analysed, the results obtained by the proposed methods are in good agreement with the labelled amounts and are comparable with the results obtained by a reported method.recovery in both the method is 98-101 %.
Anas, K; Dr. Mohammed Yusuff, K K(Cochin University of Science & Technology, April , 2003)
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Abstract:
This thesis deals with the synthesis and charcterisation of some supported
transition metal complexes and their catalytic properties. Two industrially
important reactions were carried out: i) cyclohexanol oxidation and ii)
hydrodesulphurization of diesel. Thesis is divided into nine chapters. An
overview of the heterogenised homogeneous systems is given in Chapter 1.
Chapter 2 deals with the materials and methods used for the preparation and
characterisation. Details regarding the synthesis and characterisation of zeolite
encapsulated transition metal complexes are given in Chapter 3 to Chapter 7. In
Chapter 8, the results of catalytic activity studies of the cyclohexanol oxidation
using the zeolite encapsulated complexes are presented. Details of preparation of
hydrodesulphurization catalysts through the molecular designed dispersion
method, their characterization and catalytic activity studies are presented in
Chapter 9. References are given at the end of the thesis.
Description:
Department of Applied Chemistry,Cochin University of Science and Technology
Mohammed Yusuff, K K; Arun, Vasudevan; Sreedevi, N; Robinson, P P; Manju, Sebastian(Elsevier,Journal of Molecular Catalysis A: Chemical 304 (2009) 191–198, February 7, 2009)
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Abstract:
Two new complexes, [MII(L)(Cl)(H2O)2]·H2O (where M=Ni or Ru and L = heterocyclic Schiff base, 3-
hydroxyquinoxaline-2-carboxalidene-4-aminoantipyrine), have been synthesized and characterized by
elemental analysis, FT-IR, UV–vis diffuse reflectance spectroscopy, FAB-MASS, TG–DTA, AAS, cyclic
voltammetry, conductance and magnetic susceptibility measurements. The complexes have a distorted
octahedral structure andwere found to be effective catalysts for the hydrogenation of benzene. The influence
of several reaction parameters such as reaction time, temperature, hydrogen pressure, concentration
of the catalyst and concentration of benzenewas tested. A turnover frequency of 5372 h−1 has been found
in the case of ruthenium complex for the reduction of benzene at 80 ◦C with 3.64×10−6 mol catalyst,
0.34 mol benzene and at a hydrogen pressure of 50 bar. In the case of the nickel complex, a turnover
frequency of 1718 h−1 has been found for the same reaction with 3.95×10−6 mol catalyst under similar
experimental conditions. The nickel complex shows more selectivity for the formation of cyclohexene
while the ruthenium complex is more selective for the formation of cyclohexane
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.
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
Paulraj,M; 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.
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.