The effect of glass additives on the densification , phase evolution, microstructure and microwave dielectric properties of Ba(Mg1;3
Ta2i3)03 (BMT) was investigated . Different weight percentages of quenched glass such as B203 , Si02, B203-SiO2, ZnO-B203,
5ZnO-2B2O3, Al203-SiO2, Na20-2B203.10H20, BaO-B203-SiO2, MgO-B203-SiO2, PbO-B203-SiO2 , ZnO-B203-SiO2 and
2MgO-Al203-5SiO2 were added to calcined BMT precursor . The sintering temperature of the glass -added BMT samples were
lowered down to 1300 °C compared to solid-state sintering where the temperature was 1650 °C. The formation of high temperature
satellite phases such as Ba5Ta4O15 and Ba7Ta6O22 were found to be suppressed by the glass addition . Addition of glass systems such
as B203, ZnO-B203, 5ZnO-2B203 and ZnO-B203-SiO2 improved the densification and microwave dielectric properties. Other
glasses were found to react with BMT to form low-Q phases which prevented densification . The microwave dielectric properties of
undoped BMT with a densification of 93 . 1 % of the theoretical density were Cr = 24 . 8, Tr = 8 ppm/°C and Q„ x f= 80,000 GHz. The
BMT doped with 1.0 wt% of B203 has Q„ x f = 124,700GHz, Cr = 24.2, and T f = -1.3 ppm /°C. The unloaded Q factor of 0.2 wt%
ZnO-B203-doped BMT was 136,500 GHz while that of 1.0 wt% of 5ZnO-2B203 added ceramic was Q„ x f= 141,800 GHz . The best
microwave quality factor was observed for ZnO -B203-SiO2 (ZBS) glass-added ceramics which can act as a perfect liquid-phase
medium for the sintering of BMT. The microwave dielectric properties of 0.2wt% ZBS-added BMT dielectric was
Q„ x f= 152,800 GHz, F,= 25.5, and Tr = - 1.5 ppm/°C
Ponnachan,P T C; Paulose,C S; Panikkar, K R(Department of Biotechnology, April , 1993)
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Abstract:
Alloxan induced animal model was used to evaluate the potential antidiabetic effect of A . marmelose leaf
extract. The diabetic animals were given insulin injection and another group A . marmelose leaf extract orally.
It maintained the weight of the animals near to the control rats but a significant decrease in weight was noted it
diabetic animals without any treatment . The blood elucose level in 'treated animals were near to that of control
ones. Also a significantly increased glucose tolerance was observed in animals orally given the leaf extract
prior to the experiment . A significant decrease in liver glycogen ( 1.24 -.07 s!/ 100 g of wet tissue) was observed
in diabetic rats which was brought to almost the normal level (I.84- . 14 g; 100 g) with Icaf extract treatment.
Blood urea and serum cholesterol increased ( 62.66 - 3.50 and 192.67± 13.64 mg' dl) significantly in alloxxan
diabetic rats . The leaf extract treatment decreased the blood urea and serum . cholesterol (37.83 - 3.97 and
99?0±8.43 mg/dl ) to that of control ones . A similar effect was seen with insulin treatment . The results
indicate that the active principle in .4. marmelose leaf extract has similar hypoglycaemic activity to insulin
treatment.
Simon,Chiu; Paulose,C S; Ram,K Mishra(Department of Bio Technology, July 7, 1980)
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Abstract:
Effect of L-prolyl-cinagta tlheep spyo atenndt idaol paanmti-iPnaer/nkeinusroonleiapnti cp rreocpeeprttoiers b oifn dLi-npgrso.lyPl E-LP-TleIuDcEylS- g2l(y1c)Li n1-a0lem5u-ic1dy1el1-g,(Ply1Lc9iG8n1)a. mw-Taidhsee i nm(vPeeLcstGhiag) anotinesmd n ie onuf rb oaelchetapiovtinico -suuirnbadslu eacrnevddetnarflefetueeacrrtmto
a coephfnp ePtrmLe(2icGc0iaa, lob4 mnl0y io atndnhedevl sii8tn r0oto fem dndgosoi ppktyaag mm o-1fii nn tSeehCr/eng cteiwcau tfiracuolenle edpcptattiiioiclcny r r feienoscrp et ohfpinetvos erer ad ebtali.iyncAsdit)cienusdgit ge bin nyai dfrhimacaatli nonsttpilrseytirar aiatdtuttoimeolnn u(a3aso tmfde PidgfL f hkeGargel -o(n'p2tI0ieaPr ali)ldn.y odB ll ay4-b 0icne omldlneugtdc rk eabgdsy t - c1,aa pcSthoaCrmleo)ponfrsaicypil .heP TidLn hteGoe
pahnidn esp tior odpoepraimdoinl ew raesc aelpstoo ersx ainm tihnee dst.rPiaLtuGm s,elbeuctt ihvaedly n eon ehfafneccte don t h['eH a]ffsipniirtoyp oefr tidhoel sbpiencdifinicg .b Tinhdei nbge hoafv aigouonraislt an[3dH b] iaopcohmemori--
cal results obtained in the present study raise the possibility that PLG may facilitate nigro-striatal dopaminergic neurotransmission
through interacting with a unique PLG receptor functionally coupled to the dopamine receptor cyclase complex. -adenylate
Shenoy, S D; Joy, P A; Anantharaman, M R(Elsevier, February , 2004)
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Abstract:
Nanosized ZnFe2O4 particles containing traces of a-Fe2O3 by intent were produced by low temperature chemical
coprecipitation methods. These particles were subjected to high-energy ball milling. These were then characterised using
X-ray diffraction, magnetisation and dielectric studies. The effect of milling on zinc ferrite particles have been studied
with a view to ascertaining the anomalous behaviour of these materials in the nanoregime. X-ray diffraction and
magnetisation studies carried out show that these particles are associated with strains and it is the surface effects that
contribute to the magnetisation. Hematite percentage, probably due to decomposition of zinc ferrite, increases with
milling. Dielectric behaviour of these particles is due to interfacial polarisation as proposed by Koops. Also the defects
caused by the milling produce traps in the surface layer contributes to dielectric permittivity via spin polarised electron
tunnelling between grains. The ionic mechanism is enhanced in dielectrics with the rise in temperature which results in
the increase of dielectric permittivity with temperature.
Anantharaman, M R; Muhammad, Abdul Jamal E; Mohanan, P; Joy, P A; Philip, Kurian(Springer, May 29, 2009)
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Abstract:
Nickel–rubber nanocomposites were synthesized
by incorporating ferromagnetic nickel nanoparticles in a
natural rubber as well as neoprene rubber matrix. Complex
dielectric permittivity and magnetic permeability of
these composites were evaluated in the X-band microwave
frequencies at room temperature using cavity perturbation
technique. The dielectric loss in natural rubber is smaller
compared to neoprene rubber. A steady increase in the dielectric
permittivity is observed with increase in the content
of nickel in both the composites. The magnetic permeability
exhibits a steady decrease with increase in frequency and
magnetic loss shows a relaxation at 8 GHz. The suitability of
these composites as microwave absorbers is modeled based on the reflection loss which is dependant on the real and
imaginary components of the complex dielectric permittivity
and magnetic permeability.
One-pot acetalizations of cyclohexanone. acetophenone and benzophenone were carried out using methanol over H-montmorillonite clay
(a mesoporous material). silica, alumina, and different zeolites such as HFAU-Y.HBeta, H-ZSM-5, and H-mordenite. In all the cases a single
product-the corresponding dimethylacetal-was obtained in high yields. Hemiacetal formation was not observed with any catalyst. A
comparison of catalytic activity indicated that montmorillonite K-10 is the most active catalyst for the reaction. As evidenced by the reaction
time studies, the catalyst decay is greater over the zeolite catalyst than over the clay.
Anantharaman, M R; Vaidyanathan, G; Arulmurugan, R; Likhite, S D; Milind, Vaidya; Sendhilnathan, S; Senthilram, N D(NATL INST SCIENCE COMMUNICATION, December 12, 2003)
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Abstract:
Mixed ferrites belonging to the type Mn0.9Zn0.1Fe2O4 have been prepared by the double sintering method and by the
chemical co-precipitation for comparing their magnetic properties. Sintered and precipitated ferrites exhibit different
characteristics, especially in their magnetic properties like magnetization (Ms), coercive field (Hc) and Curie temperature
(Tc). The sintered particles were size reduced in order to compare with the nanosized co-precipitated particles. The effect of
grinding has also been studied. Particles have been collected at regular intervals of grinding and their properties have been
studied. The increase in the coercive field has been recorded by a hysteresis curve tracer confirming size reduction. X-ray
diffraction studies confirmed the structure and consequent size reduction
Description:
Indian Journal of Engineering & Materials Sciences
Vol. 11, August 2004, pp. 289-294
The effect of various processing parameters, such as nip gap, friction ratio
and roll temperature, on the tensile properties of short Kevlar aramid
fibre-thermoplastic polyurethane composite has been investigated and the tensile
and tear fracture surfaces have been characterised using a scanning electron microscope.
A nip gap of 0.45 mm, a friction ratio of 1.15 and a roll temperature of 62°C
was found to give optimum mechanical properties. Scanning electron microscopy
study revealed a higher extent of fibre orientation in the milling direction in the
above condition.
Paulose,C S; Dakshinamurti,K(Department of Biotechnology, December 19, 1984)
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Abstract:
The high-affinity bindings of [3H]-5-hydroxytryptamine to serotonin S-1 receptors,
[3H]-ketanserin to serotonin S-2 receptors in the cerebral cortex, [3H]-
fluphenazine to dopamine D-1 receptors, and [3H]-spiroperidol to dopamine D-2
receptors in the corpus striatum were studied in pyridoxine-deficient rats and
compared to pyridoxine-supplemented controls. There was a significant increase
in the maximal binding (Bmax) of serotonin S-1 and S-2 receptors with a significant
decrease in their binding affinities (Kd). However, there were no significant
changes either in the maximal binding or binding affinity of striatal dopamine D-
1 and D-2 receptors. Receptor sensitivity seems to correlate negatively with the
corresponding neurotransmitter concentrations in the pyridoxine-deficient rats.
Pyroja, S; Biju,M P; Paulose,C S(Department of Biotechnology, February 11, 1998)
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Abstract:
Effect of pyridoxine on growth, metabolism and cellular activity of
freshwater prawn Macrobrachiuni rosenbergii was studied. Postlarvae
(PL-10) of M. rosenbergii were fed with clam meat containing
various concentrations of pyridoxine. After 30 days RNA and DNA
of the abdominal tissues were estimated. Length, weight and RNA
to DNA ratio increased significantly with increasing concentrations
of pyridoxine. The effect of pyridoxine on the metabolic enzyme,
malate dehydrogenase, was also studied. Vmax showed a significant
decrease and the (Km) showed a significant increase in experimental
groups compared to control.
Litty, Irimpan; Deepthy, A; Bindu, Krishnan; Kukreja, L M; Nampoori, V P N; Radhakrishnan, P(Elsevier, 2008)
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Abstract:
In the present work, we report the third order nonlinear optical properties of ZnO thin films deposited using self assembly, sol gel process as well as pulsed laser ablation by z scan technique. ZnO thin films clearly exhibit a negative nonlinear index of refraction at 532 nm and the observed nonlinear refraction is attributed to two photon absorption followed by free carrier absorption. Although the absolute nonlinear values for these films are comparable, there is a change in the sign of the absorptive nonlinearity of the films. The films developed by dip coating and pulsed laser ablation exhibit reverse saturable absorption whereas the self assembled film exhibits saturable absorption. These different nonlinear characteristics in the self assembled films can be mainly attributed to the saturation of linear absorption of the ZnO defect states.
Sreeraj, M; Sumam, Mary Idicula(IEEE, December 7, 2012)
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Abstract:
The span of writer identification extends to broad
domes like digital rights administration, forensic expert decisionmaking
systems, and document analysis systems and so on. As the
success rate of a writer identification scheme is highly dependent
on the features extracted from the documents, the phase of
feature extraction and therefore selection is highly significant for
writer identification schemes. In this paper, the writer
identification in Malayalam language is sought for by utilizing
feature extraction technique such as Scale Invariant Features
Transform (SIFT).The schemes are tested on a test bed of 280
writers and performance evaluated
Chloroprene rubber was blended with whole tire reclaimed rubber
(WTR) in presence of different levels of a coupling agent Si69 [bis-
(3-(triethoxysilyl)propy1)tetrasuIfide] and the cure characteristics and
mechanical properties were studied. The rate and state of cure were
also affected by the coupling agent. While the cure time was increased,
the cure rate and scorch time were decreased with increasing silane
content. Tensile strength, tear strength, and abrasion resistance were
improved in the presence of coupling agent. Compression set and
resilience were adversely affected in presence of silane-coupling agent.Aging studies showed that the blends containing the coupling agent
were inferior to the unmodified blends.
Blends of nitrile rubber and reclaimed rubber containing different levels of a
coupling agent, Si 69 (bis(3- triethoxysilyl propyl)(tetrasulphide) were prepared
and the cure characteristic's and mechanical properties were studied. Optimum
loading of Si-69 was found to be a function of blend ratio. 3 phi- of Si 69 in a
70:30. Blend was found to be the optimum combination with respect to the
mechanical properties. The rate and state of cure were also affected bv the
conp/ing agent. Tensile strength, tear strength and abrasion resistance were
improved in the presence of coupling agent. While the state of cure improved,
the cure rate and scorch time decreased with increasing silane content. Ageing
studies showed that the blends containing the coupling agent were inferior to
the unmodified blends.
Santhi, A; Umadevi, M; Ramakrishnan, V; Radhakrishnan, P; Nampoori, V P N(Elsevier, 2004)
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Abstract:
Nano structured noble metals have very important applications in diverse fields as photovoltaics, catalysis, electronic and magnetic devices, etc. Here, we report the application of dual beam thermal lens technique for the determination of the effect of silver sol on the absolute fluorescence quantum yield (FQY) of the laser dye rhodamine 6G. A 532 nm radiation from a diode pumped solid state laser was used as the excitation source. It has been observed that the presence of silver sol decreases the fluorescence quantum efficiency. This is expected to have a very important consequence in enhancing Raman scattering which is an important spectrochemical tool that provides information on molecular structures. We have also observed that the presence of silver sol can enhance the thermal lens signal which makes the detection of the signal easier at any concentration.
Jayaraj, M K(Electrochemical Society, July 18, 2007)
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Abstract:
ZnGa2O4:Dy3+ phosphor thin films were deposited on quartz substrates by radio frequency rf magnetron sputtering and the effect
of substrate temperature on its structural and luminescent properties was investigated. Polycrystalline film could be deposited even
at room temperature. The crystalline behavior, Zn/Ga ratio, and surface morphology of the films were found to be highly sensitive
to substrate temperature. Under UV illumination, the as-deposited films at and above 300°C gave white luminescence even
without any postdeposition treatments. The photoluminescent PL emission can be attributed to the combined effect of multicolor
emissions from the single luminescence center Dy3+ via host-sensitization. Maximum PL emission intensity was observed for the
film deposited at 600°C, and the CIE chromaticity coordinates of the emission were determined to be x,y = 0.34, 0.31 .
Sajan, D George; Augustine, S; Mathai, E; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(WILEY-VCH Verlag GmbH&Co, 2003)
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Abstract:
An open cell configuration has been employed for the photoacoustic measurement of the thermal diffusivity of undoped Bi2Se3 crystals and Bi2Se3 crystals doped with various concentrations of Te. The amplitude of the photoacoustic signal obtained under heat transmission configuration as a function of chopping frequency is used to evaluate the numerical value of thermal diffusivity, α. Doped samples show a substantial reduction in the value of α compared to undoped samples. The variations in the thermal diffusivity of the doped samples are explained in terms of the phonon assisted heat transfer mechanism. It is seen that α is very sensitive to structural variations arising from doping. The experimentally observed results are correlated with X-ray diffraction studies.