Abstract. The edge C4 graph E4(G) of a graph G has all the edges of Gas its
vertices, two vertices in E4(G) are adjacent if their corresponding edges in G are
either incident or are opposite edges of some C4. In this paper, characterizations
for E4(G)
being connected, complete, bipartite, tree etc are given. We have
also proved that E4(G) has no forbidden subgraph characterization. Some
dynamical behaviour such as convergence, mortality and touching number are also studied
Waliaula Mola,P; Sudha,B; Paulose,C S(Department of Biotechnolgy, November , 1996)
[+]
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Abstract:
The effect of insulin on cell proliferation in vivo has been studied in hepatectomised
streptozotocin- diabetic rats. The extent of cell proliferation in sham and hepatectomized- control,
diabetic and insulin treated rats were monitored by determining DNA content and [3H]thymidine
incorporation into DNA. The kinetic parameters of thymidine kinase a regulatory enzyme for
DNA synthesis was also studied in these groups. The rate of DNA synthesis in liver of
streptozotocin -diabetic rats was significantly higher 24 hrs post-hepatectomy compared to
control and insulin treated diabetic groups. Kinetic studies of thymidine kinase revealed that there
was no change in the Michaelis -Menten constant (Km) whereas maximum velocity (Vmax) was
elevated in the diabetic hepatectomized groups compared to control and insulin treated
hepatectomized groups. Thus our study elucidates the role of insulin in thymidine kinase activity
and DNA synthesis.
Ponnachan,P T C; Paulose,C S; Panikkar,K R(Department of Biotechnology, 1991)
[+]
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Abstract:
Alloxan induced diabetic animal model was
sed to evaluate the potential antidiabetic effect of
ie aqueous leaf extract of Aegle marmelose. Insuinjection
and oral treatment of Aegle marmelose
of extract to the alloxan induced rats maintained
;e animal weight near to the control rats whereas
,,ere was a significant decrease in weight in alloxan
•duced rats. Insulin injection and oral treatment
the leaf extract reversed the decrease of protein
)ntent in all the organs studied except the pancas.
Glucose level was maintained near to the co-
:rol levels in the insulin injected and leaf extract
Bated alloxan diabetic rats. A significant increased
ucose tolerance was observed in animals orally
ven the leaf extract prior to the experiment. The
suits indicate that there is an increased utilization
glucose in the Aegle marmelose leaf extract treed
rats.
Manu P, John; Jijo, P U; Nandakumaran, V M(Indian Academy of Sciences, March , 2009)
[+]
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Abstract:
We study the effect of parameter fluctuations and the resultant multiplicative
noise on the synchronization of coupled chaotic systems. We introduce a new quantity,
the fluctuation rate Ф as the number of perturbations occurring to the parameter in unit
time. It is shown that ϕ is the most significant quantity that determines the quality of
synchronization. It is found that parameter fluctuations with high fluctuation rates do not
destroy synchronization, irrespective of the statistical features of the fluctuations. We also
present a quasi-analytic explanation to the relation between ϕ and the error in synchrony.
Sony, George; Ajai, Kumar; Singh, R K; Nampoori, V P N(Springer, 2010)
[+]
[-]
Abstract:
A study has been carried out to understand the
influence of ambient gases on the dynamics of laser-blow-off
plumes of multi-layered LiF–C thin film. Plume images
at various time intervals ranging from 100 to 3000 ns have
been recorded using an intensified CCD camera. Enhancement
in the plume intensity and change in size and shape
occurs on introducing ambient gases and these changes are
highly dependent on the nature and composition of the ambient
gas used. Velocity of the plume was found to be
higher in helium ambient whereas intensity enhancement is
greater in argon environment. The plume shapes have maximum
size at 10−2 and 10−1 Torr of Ar and He pressures,
respectively. As the background pressure increases further
(>10−2 Torr: depending on the nature of gas), the plume
gets compressed/focused in the lateral direction. Internal
structure formation and turbulences are observed at higher
pressures (>10−1 Torr) in both ambient gases.
Litty, Irimpan; Ambika, D; Kumar, V; V P N Nampoori; Radhakrishnan, P(American Institute of Physics, 2008)
[+]
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Abstract:
The annealing effect on the spectral and nonlinear optical NLO characteristics of ZnO thin films
deposited on quartz substrates by sol-gel process is investigated. As the annealing temperature
increases from 300–1050 °C, there is a decrease in the band gap, which indicates the changes of the
interface of ZnO. ZnO is reported to show two emission bands, an ultraviolet UV emission band
and another in the green region. The intensity of the UV peak remains the same while the intensity
of the visible peak increases with increase in annealing temperature. The role of oxygen in ZnO thin
films during the annealing process is important to the change in optical properties. The mechanism
of the luminescence suggests that UV luminescence of ZnO thin films is related to the transition
from conduction band edge to valence band, and green luminescence is caused by the transition
from deep donor level to valence band due to oxygen vacancies. The NLO response of these
samples is studied using nanosecond laser pulses at off-resonance wavelengths. The nonlinear
absorption coefficient increases from 2.9 ×10−6 to 1.0 ×10−4 m/W when the annealing temperature
is increased from 300 to 1050 °C, mainly due to the enhancement of interfacial state and exciton
oscillator strength. The third order optical susceptibility x(3) increases with increase in annealing
temperature (T) within the range of our investigations. In the weak confinement regime, T2.4
dependence of x(3) is obtained for ZnO thin films. The role of annealing temperature on the optical
limiting response is also studied.
Cashew kernels have high
nutritive value. Upon exposure
to air kernels turn rancid and
their nutritive value decreases.
From this study it is concluded
that chemical treatment using
antioxidants reduced oxidative
rancidity but failed to prevent
deterioration in organoleptic
characteristics and decrease in
protein and carbohydrate
content of stored kernels.
Rani, Joseph(Hutig & Wepf Verlag,Basel, October 5, 1987)
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Abstract:
Compounding of styrene-butadiene copolymer/polybutadiene , natural rubber/
ethylene-propylene-diene terpolymer and natural rubber/butadiene-acrylonitrile copolymer
blends was done in three different ways and their curing behaviour and the
tensile properties of the es are compared.
James, Joseph; Ananthakrishnan, T R; Nampoori, V P N; Rudra Warier, M K; Karanjikar, N P; Kamat, M J(World Scientific Publishing Company, 1995)
[+]
[-]
Abstract:
The effect of Ce3+ on the fluorescence emission from CaS:Ce3+ phosphor is studied using X-ray excitation. Apart from the emission in the visible region, the phosphor also shows fluorescence emission in the ultraviolet region. Variation in wavelengths and intensities of these emissions due to change in dopant concentration is also analysed.
Pillai, S M; Vallabhan, C P G(Solid State Communications, 1983)
[+]
[-]
Abstract:
ZnS: Cu: Cl phosphor prepared under a vacuum firing process is found to
give blue electroluminescence with emission peak at 460 nm which remams
unaltered with the frequency of the excitation voltage. Addition of excess
chlorine in the phosphor gives blue, green and red emission at 460, 520
and 640 run. The intensity of the blue band decreases and It fmally
disappears as chlorine concentration is increased. A scheme involving
three energy levels attributed to Cu2+, Cu+ and Cl- centres in Zns
explains the experimental results completely.
The effect of chromium doping on methylene
blue sensitized Poly (vinyl alcohol)/Acrylamide was carried
out by varying the ratios of Ammonium dichromate
and methylene blue. In the case of films without ammonium
dichromate, the diffraction efficiency was found to
decrease on storage. On chromium doping the storage life
was improved. Interestingly, a self-enhancement in efficiency
was observed for a particular ratio of methylene
blue and ammonium dichromate.
Isora fibre-reinforced natural rubber (NR) composites were cured at 80, 100, 120 and
150°C using a low temperature curing accelerator system. Composites were also prepared using a
conventional accelerator system and cured at 150°C. The swelling behavior of these composites at
varying fibre loadings was studied in toluene and hexane. Results show that the uptake of solvent
and volume fraction of rubber due to swelling was lower for the low temperature cured vulcanizates
which is an indication of the better fibre/rubber adhesion. The uptake of aromatic solvent was higher
than that of aliphatic solvent, for all the composites. As the fibre content increased, the solvent
uptake decreased, due to the superior solvent resistance of the fibre and good fibre-rubber interactions.
The bonding agent improved the swelling resistance of the composites due to the strong interfacial
adhesion. Due to the improved adhesion between the fibre and rubber, the ratio of the change in
volume fraction of rubber due to swelling to the volume fraction of rubber in the dry sample (V,) was
found to decrease in the presence of bonding agent. At a fixed fibre loading, the alkali treated fibre
composite showed a lower percentage swelling than untreated one for both systems showing superior
rubber-fibre interactions.
Measurements of dc conductivity and dielectric constant show that deuteration causes an upward shift of the high temperature phase transition point from 186.5 to 191°C and a downward shift of the low temperature transition point from 10 to -1.5°C in LiNH4SO4. Mechanisms of phase transitions and of electrical transport in the crystal are discussed.
Rani, Joseph(Wiley InterScience, February 18, 2006)
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Abstract:
In this paper we report the preparation and
dielectric properties of poly o-toluidine:poly vinyl chloride
composites in pellet and film forms. The composites were
prepared using ammonium persulfate initiator and HCl
dopant. The characterization is done by TGA and DSC. The
dielectric properties including dielectric loss, conductivity,
dielectric constant, dielectric heating coefficient, absorption
coefficient, and penetration depth were studied in the
microwave field. An HP8510 vector network analyzer with
rectangular cavity resonator was used for the study. Sbands (2-4 GHz), C band (5-8 GHz), and X band (8-12
GHz) frequencies were used in the microwave field. Comparisons
between the pellet and film forms of composites
were also included. The result shows that the dielectric
properties in the microwave field are dependent on the frequency
and on the method of preparation.
Rani, Joseph(Wiley lnterScience, September 4, 2006)
[+]
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Abstract:
The latex industry has expanded over the
years to meet the world demands for gloves, condoms,
latex thread etc. Because of the strict specifications for
the products and the unstable nature of the latex, as
high as 15%, of the final latex products are rejected.
Since waste latex rubber (WLR) represents a source of
high quality rubber hydrocarbon, it is a potential candidate
for generating reclaimed rubber of superior quality.
Two types of WLR with different amounts of polysulfidic
bridges are used in these experiments, which are
reclaimed with variation of the concentration of the
reclaiming agents, the reclamation temperature and time,
Di phenyldisultide, 2-aminophenyldisulfide and 2,2'-dibenzamidodiphenyldisulfide
(DBADPDS) are used as reclaiming
agents, and the effect of diphenyldisulfides (DPDS)
with different substituents, on the reclamation efficiency of WLR is investigated. A kinetic study of the reclamation
reaction with the three reclaiming agents is done.
The reaction rates and activation energies are calculated
and compared with literature values. The comparative
study of the three different reclaiming agents shows that
(DBADPDS) is able to break the crosslinks at temperature
levels 20'C below the temperature levels normally
used with DPDS. Another advantage of this reclaiming
agent is the reduced smell during the reclamation process
and of the final reclaims, one of the most important
shortcomings of other disulfides used for this purpose.
Ravisankar, M; Reghunath, A T; Sathianandan, K; Nampoori, V P N(Optical Society of America, September 15, 1988)
[+]
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Abstract:
The split-pulse laser method is used to reinvestigate the optical attenuation of distilled water in the region from 430 to 630 nm. The studies are then extended to ionic solutions of NaCl, MgCl2, and Na2SO4, these salts forming the major constituents of seawater. The effect of the concentration of these constituents on optical attenuation is investigated. Further, optical attenuation studies are carried out for the region from 430 to 630 nm for an aqueous solution prepared with all the major constituents in the same proportions as in natural seawater. These values are then compared with values obtained for natural seawater. The relative role of dissolved salts and suspended particles on optical attenuation in seawater is discussed. The lowest attenuation is observed at ~450 nm for all solutions and is found to coincide with that for distilled water.
Mohanan,T(American Institute of Physics, August 22, 2005)
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Abstract:
The effect of dopants with different valencies and ionic radii on the densification, structural
ordering, and microwave dielectric properties of Ba(Mg1/3Ta2/3)O3 (BMT) is investigated. It is
found that dopants such as Sb2O5, MnO, ZrO2, WO3, and ZnO improve the microwave dielectric
properties of BMT. Addition of trivalent dopants is detrimental to the cation ordering and dielectric
properties of BMT. A correlation between the microwave dielectric properties of BMT and ionic
radii of the dopant has been established. The variation of the dielectric properties of pure and doped
BMT at cryogenic temperatures is also discussed.
Surendran,K P; Sebastian,M T; Mohanan,P; Mohanan,Jacob V(American Institute of Physics, 2005)
[+]
[-]
Abstract:
The effect of dopants with different valencies and ionic radii on the densification, structural
ordering, and microwave dielectric properties of Ba(Mg1t3Tazt3)O3 (BMT) is investigated. It is
found that dopants such as Sb,05, MnO, ZrO,, WO1, and ZnO improve the microwave dielectric
properties of BMT. Addition of trivalent dopants is detrimental to the cation ordering and dielectric
properties of BMT. A correlation between the microwave dielectric properties of BMT and ionic
radii of the dopant has been established. The variation of the dielectric properties of pure and doped
BMT at cryogenic temperatures is also discussed
Rani, Joseph(John Wiley & Sons, Inc., June 21, 2001)
[+]
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Abstract:
ABSTRACT: Polyaniline was synthesized by using ammonium persulfate initiator in the
presence of 1M HC1. It was dried under different drying conditions like room temperature
drying (for 48 h), oven drying (at 50-60°C for 8 h under a vacuum), and vacuum
drying (at room temperature for 16 h). The conductivities of these samples were
measured at microwave frequencies. These samples were also pelletized and the
measurements were repeated. The cavity perturbation technique was used for the
study.