Ramya, R; Dr.Balasundaran, M; Dr.Jose, Kallarackal(Kerala Forest Research Institute, July , 2010)
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Abstract:
S. album L. is the source of highly priced and fragrant heartwood which on steam
distillation yields on an average 57
per cent oil of high perfumery value. Global
demand for sandalwood is about 5000-6000
tons/year and that of oil is 100 tons/year.
Heartwood of sandal is estimated to fetch up to Rs. 3.7 million/ton and wood oil
Rs.70,000-100,000/
kg in the international market. Sandal heartwood prices have
increased from Rs. 365/ton in 1900 to Rs. 6.5 lakhs/ton in 1999-2000
and to Rs. 37
lakhs/ton in 2007. Substantial decline in sandalwood production has occurred from 3176
tons/year during 1960-‘
65 to 1500 tons/year in 1997-98,
and to 500 tons/year in 2007.Depletion of sandal resources is attributed to several factors, both natural and
anthropogenic. Low seed setting, poor seed germination, seedling mortality, lack of
haustorial connection with host plant roots, recurrent annual fires in natural sandal
forests, lopping of trees for fodder, excessive grazing, hacking, encroachments, seedling
diseases and spread of sandal spike disease are the major problems facing sandal. While
these factors hinder sandal regeneration in forest areas, the situation is accelerated by
human activities of chronic overexploitation
and illicit felling.Deterioration of natural sandal populations due to illicit felling, encroachments and
diseases has an adverse effect on genetic diversity of the species. The loss of genetic
diversity has aggravated during recent years due to extensive logging, changing landuse
patterns and poor natural regeneration. The consequent genetic erosion is of serious
concern affecting tree improvement programme in sandal. Conservation as well as mass
propagation are the two strategies to be given due importance. To initiate any
conservation programme, precise knowledge of the factors influencing regeneration and
survival of the species is essential. Hence, the present study was undertaken with the
objective of investigating the autotrophic and parasitic phase of sandal seedlings
growth, the effects of shade on morphology, chlorophyll concentration and chlorophyll
fluorescence of sandal seedlings, genetic diversity in sandal seed stands using ISSR
markers, and the diversity of fungal isolates causing sandal seedling wilt using RAPD
markers. All these factors directly influence regeneration and survival of sandal
seedlings in natural forests and plantations.
Mathiazhagan, A; Dr.Rani, Joseph; Dr.Narayanan, K P(Cochin University of Science & Technology, January , 2011)
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Abstract:
Brasses are widely used as constructional materials in marine environment due to their anticorrosive,antifouling and mechanical properties.However, its resistance to corrosion and fouling may vary according to local marine environmental condition and the seasons.The dezincification of brass is one of the forms of selective corrosion which has attracted the attention of researchers for the last two decades.Many of the dezincification mechanistic studies have been performed in noncomplex media and hence their conclusions cannot be extended to esturine water,which is of great significance since brass is extensively used in marine environment.Inhibited α brasses are largely immune to dezincication and the effect of tin and arsenic addition to α/beta brasses is not so reliable in controlling the dezincification. There have been many cases of dezincification in duplex brasses in both freshwater and seawater.Though there is some protection methods such as inhibitors,electro deposition and electro polymerization,there is no reliable method of inhibiting the dezincification of two-phase brass.Organic coatings are effectively used for the protection metals due to their capacity to act a physical barrieer between the metal surface and corrosive environment.Hence,pure epoxy coating is selected for this as it has antocorrosiion effect on brass.The dezincification behaviour of brass of the present study has been highlighted in terms of corrosion rate,weight gain/loss,corrosion current and polarization resistence,open circuit potential,dezincification factor. The marine fouling as biomass on brass was assessed and presented in this thesis, The physicochemical properties of estuarine water were correlated with corrosion behaviour of brass.The deterioration of the brass subjected to the effect of estuarine water was also investigated as a measure of loss in mechanical properties such as tensile strength,yield strength,percntage elongation and percentage reduction in area.To validate dezincification data,visual observation,spot analysis,surface morphology before and after removal of corrosion products and corrosion product analysis were performed.The dezincification behavior of epoxy coated brass of the present study has beenhighlighted in terms of corrosion rate ,weight gain/loss,corrosion current and polarization resistance,open circuit potential.dezincification factor.The marine fouling as biomass on epoxy coated brass subjeted to the effect of estuarine water was also investigated as ameasure of loss in mechanical properties such as tensile strength,percentage elongation and percentage reduction in area.The results of dezincification behavior of brass and epoxy coated brass in Cochin estuary water has been presented and discussed.Attempt has been made to correlate the dezincification behavior of brass with epoxy coated brass.
Description:
Dept.of Ship Technology,Cochin University of Science and Technology
Manoj, Joseph; Dr.Mohanan, P(Cochin University of Science & Technology, October , 2010)
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Abstract:
The thesis is the outcome of the theoretical and experimental investigations on mocrostrip-fed printed strip monopole antenna.Finite ground plane has been effectively utilized to excite a new resonance near the fundamental mode by introducing another extended strip from the ground plane,without affecting compactness.Further size reduction was achieved by carrying out folding analysis on dual strip antenna and a compact folded dual strip antenna has been designed.Design methodologies for both the compact dual band antennas are presented.The proposed antennas can be used for mobile and WLAN applications due to wide bandwidth,moderate gain and omnidirectional radiation coverage.
Description:
Department of
Electronics, Cochin University of Science and Technology.
Bhuvaneswary, M G; Dr. Eby Thomas, Thachil(Cochin University of Science & Technology, February , 2010)
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Abstract:
This thesis presents the findings of a study on incorporating vanous
thermoset resins into natural rubber for property improvement. Natural rubber
is an important elastomer with the unique attribute of being a renewable
agricultural product. The study was undertaken to investigate the extent to
which the drawbacks of natural rubber, especially its poor thermal and oil
resistance propel1ies could be nullified by blending with common thermoset
resins. A thorough and comparative understanding of the perfonnance of
different resins from this viewpoint will be beneficial for both natural IUbber
processors and consumers. In this study the thennoset resins used were epoxy
resin, phenolics, epoxidised phenolics and unsaturated polyester resin.The resins were incorporated into NR during compounding and their
effects on the properties of NR were studied after vulcanization. Properties
were studied for both gum and filled N R compounds. The important properties
studied are cure characteristics, mechanical properties, ageing propel1ies,
thermal propel1ies, crosslink density and extractability. Characterization studies
were also conducted using FTIR, TGA and DSC.Improvement in mechanical properties was noticed in many cases. The
results show that most resins lead to a reduction in the cure time of NR. The
perfonnance of epoxy resin is most noticeable in this respect. Mechanical
properties of the modified IUbber show maximum improvement in the case of
epoxidised novolacs. Most resins are seen to improve the thermal and oil
resistance propel1ies of NR. Epoxy novolacs show maximum effect in this
respect also. However the presence of tillers is found to moderate the positive
effects of the thermoset resins considerably.
Description:
Department of Polymer
Science and Rubber Technology, Cochin University of Science and
Technology