Sujatha, C H; Aneeshkumar, N(Elsevier, January 2, 2012)
[+]
[-]
Abstract:
Sedimentary biomarker pigments around Cochin estuary situated in the southwest coast of India were
determined by HPLC. Fucoxanthin, an indicator of diatom was observed to be the most abundant
carotenoid pigment in the estuary. Dinoflagellate derived carotenoid pigment peridinin was confined in
the southern part of estuary and zeaxanthin pigment indicative of cyanobacteria were more found in
sites influenced by anthropogenic activities. One compound having close similarity to fucoxanthin was
also detected. Alloxanthin (cryptophyceae), chl b (green algae), canthaxanthin, neoxanthin, lutein and
peridinin isomer were also detected by spectra and corresponding algal class were identified. The highest
concentration of chl a (11.01 mg g 1) found near to the anthropogenic affected area while the lowest chl
a (0.65 mg g 1) was recorded in industrial area. Degradation products of chl a, such as pheophorbide and
pheophytin were observed and principal mode of mechanism of degradation were derived. Higher
pheopigments content than chl a, reflects a density trapping of dead cells and early degradation of
phytopigments from grazing activities
Description:
Estuarine, Coastal and Shelf Science 99 (2012) 182-190
Mechanical properties and thermal degradation characteristics of natural rubber compounds
captaining coconut oil were compared with that of a control compound containing naphthenic oil.
Cure time was marginally lower in the case of coconut oil mixes, probably due to the presence of
free fatty acids. Tensile strength , tear strength, resilience and abrasion resistance were better than
the naphthenic oil-based compounds . Compression set and hardness were marginally inferior
The coconut oil mixes had a crosslink density comparable to that of the reference compound.
Thermal studies showed that the temperature of initiation of degradation was increased by 10°C
and the temperature at which the peak rate of degradation occured was increased by 7°C. The
peak rate of degradation was compa rable to the control compound.
Sunil,K Narayanankutty(Elsevier Science Limited, May 17, 1997)
[+]
[-]
Abstract:
The thermal degradation of short polyester fiber reinforced polyurethane composites
with and without different bonding agents has been studied by thermogravimetric
analysis . It was found that degradation of the polyurethane takes
place in two steps and that of the composites takes place in three steps. With
the incorporation of 30 phr of fiber in the matrix , the onset of degradation was
shifted from 230 to 238 ° C. The presence of bonding agents in the virgin elastomer
and the composite gave an improved thermal stability . Results of kinetic studies
showed that the degradation of polyurethane and the reinforced composites with
and without bonding agents follows first -order reaction kinetics