The cure characteristics of short fiber-polyurethane elastomer
were studied with respect to different fiber-matrix bonding agents. A hexamethylenetetramine-
resorcinol -hydrated silica based bonding agent was found to affect
the stability of the composite. A new bonding agent, TP resin, based on polymeric
toluenediisocyanate and polypropylene glycol has been developed. Cure characteristics
of the composite with and without TP resin at different fiber loadings were
also compared. Minimum torque, scorch time and optimum cure time increased
with fiber content. Maximum torque was consistently higher with TP resin at all
fiber loadings.
Rani, Joseph(Wiley Inter Science, December 14, 2005)
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Abstract:
Polypyrrole/poly (vinyl chloride) semi-interpenenzrtirtg
networks of different compositions are prepared using anunonitun per
sulfate initiator at room temperature in pellet.form and lilrrt form and
their dielectric properties are studied at different microwave frequencies.
An HP 8510 Vector network analyzer interfaced with a computer
is used. The cavity-perturbation technique is employed for the
study
Rani, Joseph(Wiley Periodicals, Inc., October 23, 2003)
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Abstract:
Poly(o-toluidine) (PoT) and poly(o-toluidine
co aniline) were prepared by using ammonium persulfate
initiator, in the presence of 1M HCI. It was dried under
different conditions: room temperature drying (48 h), oven
drying (at 50°C for 12 h), or vacuum drying (under vacuum,
at room temperature for 16 h). The dielectric properties, such
as dielectric loss, conductivity, dielectric constant, dielectric
heating coefficient, loss tangent, etc., were studied at microwave frequencies. A cavity perturbation technique was used
for the study. The dielectric properties were found to be
related to the frequency and drying conditions. Also, the
copolymer showed better properties compared to PoT alone.
Rani, Joseph(John Wiley & Sons, Inc., November 8, 2000)
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Abstract:
ABSTRACT: The dipping characteristics of radiation-vulcanized natural rubber latex
and natural rubber latex compounds were investigated with a lab-model semiautomatic
dipping machine. The effect of the variation of the speed of immersion and withdrawal,
dwell time, compound viscosity, and concentration of coagulant on the thickness of the
latex deposit was investigated. The results of the study show that the deposit thickness
depends on the withdrawal speed of the former, the concentration of the coagulant,
dwell times, and the viscosity of the latex compounds
The effect of an external flaw on the tensile strength of short kevlar fiber-thermoplastic
composites has been studied with respect to fiber content, fiber orientation,
location of the external flaw, and the temperature of test. The composites showed
a three-step reduction in tensile strength with increasing flaw size. The critical flaw-length
region was shifted to higher flaw-size levels with increasing fiber content. With increasing
temperature, the critical flaw length was increased in the case of unfilled TPU, whereas it
remained more or less constant in the case of short kevlar fiber-filled-TPU composite.
Sunil,K Narayanankutty(Technomic Publishing Co., Inc., June 1, 1992)
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Abstract:
The flammability of short Kevlar aramide fiber-thermoplastic
polyurethane (TPU) has been investigated with respect to fiber loading and
various flame retardant additives such as halogen containing polymers, antimony
oxide/chlorine donor combination, zinc borate, and aluminum hydroxide.
Smoke generation was reduced drastically, while the oxygen index was reduced
marginally in the presence of short fibers. The best improvement in the oxygen
index was obtained with antimony oxide/chlorinated paraffin wax combination,
in the weight ratio 1:6. A 70 phr loading of aluminum hydroxide improved LOI
and reduced smoke generation.
Anantharaman, M R; Saravanan, S; Venkatachalam, S; Avasthi, D K(Elsevier, March 26, 2007)
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Abstract:
Polyaniline thin films prepared by RF plasma polymerisation were irradiated with 92MeV Si ions for various fluences of 1 1011,
1 1012 and 1 1013 ions/cm2. FTIR and UV–vis–NIR measurements were carried out on the pristine and Si ion irradiated polyaniline
thin films for structural evaluation and optical band gap determination. The effect of swift heavy ions on the structural and optical
properties of plasma-polymerised aniline thin film is investigated. Their properties are compared with that of the pristine sample. The
FTIR spectrum indicates that the structure of the irradiated sample is altered. The optical studies show that the band gap of irradiated
thin film has been considerably modified. This has been attributed to the rearrangement in the ring structure and the formation of CRC
terminals. This results in extended conjugated structure causing reduction in optical band gap
Latex waste products contain rubber hydrocarbon of very high
quality, which is only lightly cross linked. Selected wastes such as thread waste
and glove waste were modified into processable materials by a novel economic
process and thermoplastic elastomers were prepared by blending these modified
waste materials with high density polyethylene in various proportions. The
mechanical properties as well as the rheological behaviour of these blends were
evaluated and compared with those of the natural rubber-high density
polyethylene blends.
Latex waste like glove waste was effectively modified using a new reclaiming
agent, thiocarbanilide. This modified waste was blended with linear low-density
polyethylene (LLDPE) to develop a novel thermoplastic elastomer. Both uncrosslinked
and dynamically crosslinked blends were prepared and their properties
were studied. The results were found to be comparable to those of conventional
thermoplastic elastomers.
Achamma, Kurian; Thomas Lee, S; Unnikrishnan, K P; Sajan, D George; Nampoori, V P N; Vallabhan, C P G(World Scientific, 2003)
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Abstract:
Two-photon absorption spectrum of aniline is recorded using thermal lens effect with
optical parametric oscillator as the pump source. Studies show that the two-photon
absorption spectrum observed corresponds to I Al -. I B2 transition of aniline.
Zinc butyl xanthate [Zn(bxt)2] was prepared
in the laboratory . The effect of this xanthate with zinc
diethyl dithiocarbamate (ZDC) on the vulcanization of natural
rubber ( NR), polybutadiene rubber (BR), and NR/BR
blend has been studied at different temperatures. The
amounts of Zn (bxt)2 and ZDC in the compounds were optimized
by varying the amount of ZDC from 0 . 75 to 1.5 phr
and Zn (bxt)2 from 0 . 75 to 1 .5 phr. The cure characteristics
were also studied . HAF filled NR, BR, and NR / BR blend
compounds were cured at different temperatures from 60 to
150 C. The sheets were molded and properties such as tensile strength, tear strength, crosslink density and elongation
at break, compression set, abrasion resistance, etc. were
evaluated. The results show that the mechanical properties
of 80NR/20BR blends are closer to that of NR vulcanizates,
properties of 60NR/40BR blends are closer to BR vulcanizates,
while the 70NR/30BR blends show an intermediate
property.
Saleena, Mathew; Maya, Raman(Springer, March 14, 2012)
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Abstract:
The chemical composition and evaluation of Indian
squid (Loligo duvauceli) mantle, epidermal connective
tissue and tentacle is investigated in this current study. It is
observed that squid mantle contains 22.2% total protein;
63.5% of the total protein is myofibrillar protein. The unique
property of squid myofibrillar protein is its water solubility.
Squid mantle contains 12.0% total collagen. Epidermal connective
tissue has highest amounts of total collagen (17.8%).
SDS-PAGE of total collagen identified high molecular
weight α-, β- and γ- sub-chains. Amino acid profile analysis
indicates that mantle and tentacle contain essential
amino acids. Arginine forms a major portion of mantle
collagen (272.5 g/100 g N). Isoleucine, glutamic acid and
lysine are other amino acids that are found in significantly
high amounts in the mantle. Sulphur containing cystine is
deficit in mantle collagen. Papain digest of mantle and
epidermal connective tissue is rich in uronic acid, while
papain digest, collagenase digest and urea digest of epidermal
connective tissue has significant amounts of sialic acid
(25.2, 33.2 and 99.8 μmol /100 g, respectively). PAS staining
of papain digest, collagenase digest and urea digest also
identify the association of hexoses with low molecular
weight collagen fragments. Histochemical sectioning also
emphasized the localized distribution of collagen in epidermal
and dermal region and very sparse fibres traverse the
myotome bundles
Ramankutty, C G; Sugunan, S; Bejoy, Thomas(Elsevier, September 9, 2002)
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Abstract:
Preparation of simple and mixed ferrospinels of nickel, cobalt and copper and their sulphated analogues by the room temperature coprecipitation method yielded fine particles with high surface areas. Study of the vapour phase decomposition of cyclohexanol at 300 °C over all the ferrospinel systems showed very good conversions yielding cyclohexene by dehydration and/or cyclohexanone by dehydrogenation, as the major products. Sulphation very much enhanced the dehydration activity over all the samples. A good correlation was obtained between the dehydration activities of the simple ferrites and their weak plus medium strength acidities (usually of the Brφnsted type) determined independently by the n-butylamine adsorption and ammonia-TPD methods. Mixed ferrites containing copper showed a general decrease in acidities and a drastic decrease in dehydration activities. There was no general correlation between the basicity parameters obtained by electron donor studies and the ratio of dehydrogenation to dehydration activities. There was a leap in the dehydrogenation activities in the case of all the ferrospinel samples containing copper. Along with the basic properties, the redox properties of copper ion have been invoked to account for this added activity.
Reghunath, A T; Nampoori, V P N(Springer, November , 1987)
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Abstract:
Using laser transmission, the characteristics of hydrodynamic turbulence is studied following one of the recently developed technique in nonlinear dynamics. The existence of deterministic chaos in turbulence is proved by evaluating two invariants viz. dimension of attractor and Kolmogorov entropy. The behaviour of these invariants indicates that above a certain strength of turbulence the system tends to more ordered states.
Sheeja, N K(Emerald Group Publishing Limited, March 10, 2010)
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Abstract:
The purpose of this paper is to examine the information-seeking behavior of science and
social science research scholars, including service effectiveness, satisfaction level on different type of
sources and various methods adopted by the scholars for keeping up to dateData were gathered using a questionnaire survey of 200, randomly
selected, PhD students of science and social science departments of four universities in Kerala, IndiaAlthough similarities exist between social science and science PhD students with regard to
information-seeking behavior, there are significant differences as well. There is a significant difference
between science and social science scholars on the perception of the adequacy of print journals and
database collection which are very relevant to the research purposes. There is no significant difference
between science and social science scholars on the perception of the adequacy of e-journals, the most
used source for keeping up to date. The study proved that scholars of both the fields are dissatisfied
with the effectiveness of the library in keeping them up to date with latest developments
Harilal, S S; Riju, C Issac; Bindhu, C V; Nampoori, V P N; Vallabhan, C P G(World Scientific Publishing Company, 1996)
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Abstract:
Laser ablation processes in liquid benzene, toluene and carbon disulphide have been investigated by pulsed photoacoustic technique using 532 nm radiation from a frequency doubled Q-switched Nd:YAG laser. The nature of variation of photoacoustic signal amplitude with laser energy clearly indicates that different phenomena are involved in the generation of photoacoustic effect and these are discussed in detail. Our results suggest multiphoton induced photofragmentation as the most plausible interaction process occurring during laser ablation in these liquids.
Riju, C Issac; Bindhu, C V; Harilal, S S; Geetha K, Varier; Nampoori, V P N; Vallabhan, C P G(World Scientific Publishing Company, 1996)
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Abstract:
Pulsed photoacoustic studies in solution of C60 in toluene have been made using the 532 nm radiation from a frequency doubled Nd:YAG laser. Though C60 is found to exhibit the phenomenon of optical limiting, the results on photoacoustic measurements do not give any indication of multiphoton transitions as suggested in some of the earlier works. Results of photoacoustic measurements show that excited state absorption is the dominant process responsible for optical limiting while phenomena like nonlinear scattering may contribute to a lesser extent.
Ritty J, Nedumpara; Thomas, K J; Jayasree, V K; Girijavallabhan, C P; Nampoori, V P N; Radhakrishnan, P(Optical Society of America, July 20, 2007)
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Abstract:
The results of a brief investigation of the amplified spontaneous emission and lasing characteristics of Coumarin 540 dye in as many as ten different solvents are reported. It has been found that C 540 dye solutions contained within a rectangular quartz cuvette give laser emission with well resolved equally spaced modes when pumped with a 476 nm beam. The modes were found to originate from the subcavities formed by the plane-parallel walls of the cuvette containing the high-gain medium. While the quantum yield remains a decisive factor, a clear correlation between the total width of the emission spectra and the refractive indices of the solvents of the respective samples has been demonstrated. The well-resolved mode structure exhibited by the emission spectra gives clear evidence of the lasing action taking place in the gain medium, and the number of modes enables us to compare the gain of the media in different samples. A detailed discussion of the solvent effect in the lasing characteristics of C540 in different solutions is given.
Rani, Joseph(OPA (Overseas Publishers Association), July 15, 1994)
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Abstract:
The mechanical properties of filled natural rubber latex vulcanizates were found to be improved by the
addition of polyethylene glycols of different molecular weight and glycerol. There is a slight reduction
in the optimum cure times of the compounds containing PEG/Glycerol. The morphology study shows
that the filler distribution is more uniform in the compounds containing PEG/Glycerol.
Dr.Babu, C A; Jayakrishnan, P R((http://www.scirp.org/journal/acs), July , 2013)
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Abstract:
Oceans play a vital role in the global climate system. They absorb the incoming solar energy and redistribute the energy through horizontal and vertical transports. In this context it is important to investigate the variation of heat budget components during the formation of a low-pressure system. In 2007, the monsoon onset was on 28th May. A well- marked low-pressure area was formed in the eastern Arabian Sea after the onset and it further developed into a cyclone. We have analysed the heat budget components during different stages of the cyclone. The data used for the computation of heat budget components is Objectively Analyzed air-sea flux data obtained from WHOI (Woods Hole Oceanographic Institution) project. Its horizontal resolution is 1° × 1°. Over the low-pressure area, the latent heat flux was 180 Wm−2. It increased to a maximum value of 210 Wm−2 on 1st June 2007, on which the system was intensified into a cyclone (Gonu) with latent heat flux values ranging from 200 to 250 Wm−2. It sharply decreased after the passage of cyclone. The high value of latent heat flux is attributed to the latent heat release due to the cyclone by the formation of clouds. Long wave radiation flux is decreased sharply from 100 Wm−2 to 30 Wm−2 when the low-pressure system intensified into a cyclone. The decrease in long wave radiation flux is due to the presence of clouds. Net heat flux also decreases sharply to −200 Wm−2 on 1st June 2007. After the passage, the flux value increased to normal value (150 Wm−2) within one day. A sharp increase in the sensible heat flux value (20 Wm−2) is observed on 1st June 2007 and it decreased there- after. Short wave radiation flux decreased from 300 Wm−2 to 90 Wm−2 during the intensification on 1st June 2007. Over this region, short wave radiation flux sharply increased to higher value soon after the passage of the cyclone.
Description:
Atmospheric and Climate Sciences, 2013, 3, 282-290