Jayaraj, M K(Electrochemical Society, July 18, 2007)
[+]
[-]
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)
[+]
[-]
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.
Anantharaman, M R; Hysen, T; Saravanan, S; Deepa, S; Ramanujan, R V; Avasthi, D K; Kulkarni, S D; Joy, P A(IOP Publishing LTD, May 5, 2006)
[+]
[-]
Abstract:
Magnetic properties of nano-crystalline soft magnetic alloys have usually
been correlated to structural evolution with heat treatment. However,
literature reports pertaining to the study of nano-crystalline thin films are
less abundant. Thin films of Fe40Ni38B18Mo4 were deposited on glass
substrates under a high vacuum of ≈ 10−6 Torr by employing resistive
heating. They were annealed at various temperatures ranging from 373 to
773K based on differential scanning calorimetric studies carried out on the
ribbons. The magnetic characteristics were investigated using vibrating
sample magnetometry. Morphological characterizations were carried out
using atomic force microscopy (AFM), and magnetic force microscopy
(MFM) imaging is used to study the domain characteristics. The variation of
magnetic properties with thermal annealing is also investigated. From AFM
and MFM images it can be inferred that the crystallization temperature of
the as-prepared films are lower than their bulk counterparts. Also there is a
progressive evolution of coercivity up to 573 K, which is an indication of the
lowering of nano-crystallization temperature in thin films. The variation of
coercivity with the structural evolution of the thin films with annealing is
discussed and a plausible explanation is provided using the modified random
anisotropy model
Rani, Joseph(Wiley InterScience, December 13, 2004)
[+]
[-]
Abstract:
Prevulcanized natural rubber latex was prepared
by the heating of the latex compound at 55°C for
different periods of time (2, 4, 6, 8, and 10 h). The changes in
the colloidal stability and physical properties were evaluated
during the course of prevulcanization. The prevulcanized
latex compounds were stored for 300 days, and the
properties were monitored at different storage intervals (0,
20, 40, 60, 120, 180, 240, and 300 days). During prevulcanization,
the mechanical stability time increased, and the viscosity
remained almost constant. The tensile strength increased
during storage for a period of 20 days. The degree of
crosslinking, modulus, elongation at break, and chloroform
number were varied with the time of storage.
The cure characteristics and mechanical properties of short nylon fiber- styrene
/whole tyre reclaim (SBR/WTR) composites with and without
an interfacial bonding agent based on 4,4 diphenyl methane diisocyanate and
polyethylene glycol (MDI/PEG) have been studied. An 80:40 blend of SBR/
WTR reinforced with 20 phr of short nylon fiber has been selected and the MDI/
PEG ratio has been changed from 0.67:1 to 2:1. The minimum and maximum
torques increased with isocyanate concentration. The scorch time and cure time
showed an initial reduction. The cure rate showed an initial improvement.
Tensile strength, tear strength and abrasion resistance increased with MDI/PEG
ratio, these values were higher in longitudinal direction. Resilience and
compression set increased with isocyanate concentration.
Sugunan, S; Renuka, N K(Indian Journal of Chemistry, April , 2002)
[+]
[-]
Abstract:
Physico-chemical characterization of DY203/V2O5 systems prepared through wet impregnation method has been carried
out using various techniques like EDX, XRD, FTIR. thermal studies, BET surface area, pore volume and pore size
distribution analysis. The amount of vanadia incorporated has been found to influence the surface properties of dysprosia.
The spectroscopic results combining with X-ray analysis reveal that vanadia species exist predominantly as isolated
amorphous vanadyl units along with crystalline dysprosium orthovanadate. Basicity studies have been conducted by
adsorption of electron acceptors and acidity and acid strength distribution by temperature programmed desorption of
ammonia. Cyclohexanol decomposition has been employed as a chemical probe reaction to examine the effect of vanadia on
the acid base property of Dy2O3. Incorporation of vanadia titrates thc Lewis acid and base sites of Dy2O3, while an
enhancement of Bronsted acid sites has been noticed. Data have been correlated with the catalytic activity of these oxides
towards the vapour phase methylation of phenol
Cilla Abraham; Dr.Radhakrishnan,C K(Cochin University Of Science And Technology, November , 2012)
[+]
[-]
Abstract:
The main objective of the present work is to acquire information
regarding the growth responses of P. monodon larvae (from PZ1 upto PL1)
to various mono specific and mixed diets. Evaluate the nutritional quality of
selected species of micro algae viz. Chaetoceros calcitrans, Dunaliella
salina, Isochrysis galbana and Nannochloropsis salina, larvae at three cell concentrations 10x104 cells/ml, 25x104 cells/ml and
50x104 cells/ml.
The P. monodon larvae were transported, at the Nauplius stage, to the
laboratory. The larvae were stocked at density of 150 larvae per litre in 5 litre
FRP tanks with 3 litres of sea water. The algal cell density given to the larvae
varied. The larval stages were fed with increasing densities of algae to
evaluate the relationship between the food densities, ingestion rates,
development and growth of the larvae. The water quality parameters, the
percentage of survival rate, the growth estimation and the algal cell count
were done. Each experiment was carried out in triplicate with a control group
of larvae fed with Chaetoceros calcitrans. For the estimation standard
procedures were used.to P. monodon
Description:
Dept. of Marine Biology,
Microbiology and Biochemistry.
Cochin University of
Science and Technology
Bikash Chandra, Mohapatra; Dr.Rengarajan, K(Cochin University Of Science And Technology, August , 1993)
[+]
[-]
Abstract:
The research investigations on pollution, particularly in coastal/
estuarine environments are recent ones and started only in 1970s. Hence
the informations available are fragmentary and scattered. They throw
some light only on either the concentration of heavy metals in water
or in sediment or in organisms. No concerted efforts have been made
to consolidate and correlate the results between the environment and
biota. Literature on the level of concentration of heavy metals in different
tissues of organisms with regard to their availability in the living media,
their ratio, their inter—relationship, tolerance limit of organisms, etc. are
very few or rather nil.
in view of the importance enumerated above, the candidate has
selected the topic "Effects of some heavy metals copper, zinc and lead
on certain tissues of E E (Hamilton and Buchanan) in different
environments" for detailed studies and to understand systematically (i)
the source of effluents and wastes, (ii) the concentration of heavy metals
copper, zinc and lead in water, in sediments and in tissues of the test
animal, (iii) their effects, (iv) capacity of tolerance and accumulation
in different tissues of the animal, and (V) the "Bioaccumulation Factor",
etc.
Description:
Department Of Marine Sciences, Cochin University Of Science And Technology
Ashokakumaran, Unnithan K; Dr.Menon,N R; Dr.Kuttyamma, V J(Cochin University Of Science And Technology, August , 1997)
[+]
[-]
Abstract:
The present research programme envisages a comparative study of the effects of
two piscicides of plant origin, viz., mahua oil cake, a derivative from the plant fig
Iatifolia and croton seed, a product from the plant Croton tiglium. Although some reports
on the effects of mahua oil cake and croton seed on fresh water pond culture systems are
available, information on their effect on brackishwater culture systems are rather scanty
This was the guiding principle for launching the present study It is hoped that the findings
will enable aquaculturists to make use of the piscicides in a more rational and efficient
way, and will go a long way towards realising the maximum return liom culture systems
without hampering the environment.
The thesis is presented in seven chapters such as Introduction, Review of
literature, Materials and Methods, Results, Discussion, Summary and Bibliography
Description:
School of Marine Sciences. Cochin University of Science and
Technology
Sebastian, Thomas; Dr.Meera Bai,M(Cochin University of Science And Technology, July , 2013)
[+]
[-]
Abstract:
one of the key sectors, identified by the
Department of Industries Government of Kerala, for the cluster development
initiative is Handloom, which gives employment to over over 50,000 people
directly. Despite its age old tradition and fame, the performance of the sector
vis-à-vis power looms is not very rosy owing to (i) competition from cheap
power loom cloth from other states (ii) scarcity of quality yarn (iii) price
escalation of yarn, dyes, chemicals and other raw materials (iv) the shrinking
market for handlooms in Kerala (v) non-demand based production and
inadequacy of new designs and (vi) inefficiencies in the system, particularly in
the co-operative sector. Cluster based approach is adopted in the handloom
sector with the objective of providing necessary support mechanism to come out of the crisis that the sector faces now. While four cluster schemes are being
implemented in Kerala, it is under IHDS-CDP that the State got a sizeable
number of clusters benefiting a large number of societies and weavers- 24
handloom clusters, bringing 152 handloom co-operative societies and over
19,800 handloom workers under the Programme.
This research attempts to revisit the underlying rationale and context of
the new direction and would attempt to broadly analyze the growth trends under
the influence of cluster model adopted by the State IHDS-CDP for the revival
of handloom sector through a detailed study of the handloom co-operative
societies in Kerala. If handloom sector in Kerala can be revived using cluster
based approach, it can be easily concluded that cluster is capable of taking the
MSME in Kerala to a ‘high growth path.’ The study is aimed at understanding
how best clusters emerge as appropriate industrial organization suitable for the
current global structure of manufacture
Description:
Department of Applied Economics,Cochin University Of Science And Technology
Bright Singh, I S; PhIlip, R; Amar, B(Blackwell Publishing, June 19, 2006)
[+]
[-]
Abstract:
Prawn shell waste collected from shrimp-processing plants in
Cochin, India, was subjected to fermentation using 20
chitinoclastic and proteolytic/non-proteolytic bacterial
strains. The products generated were analysed for protein,
lipid, total sugars, N-acetyl glucosamine, free amino acids
and ash. Shrimp diets were prepared using these 20 fermented
products and a control diet using raw prawn shell
waste. Feeding experiment was conducted with postlarvae
(PL21) of Indian white prawn, Fenneropenaeus indicus for a
period of 21 days. Biogrowth parameters such as mean
weight gain, feed conversion ratio, specific growth rate and
protein efficiency ratio were estimated and the animals were
challenged with white spot virus orally via diet. Enhanced
growth could be observed in prawns fed F134 and F124,
incorporated with the fermentation products generated using
Bacillus spp., C134 and C124 respectively. The percentage
survival of prawns after 7 days of challenge was found to be
highest for groups fed diet F111 incorporated with fermentation
product generated using Bacillus sp. These products of
bacterial fermentation hold promise as growth enhancers and
immunostimulants in aquaculture.
KEY WORDS: biogrowth parameters, feed
Antony,M T; Jose,T Payyappilly(Department of Applied Economics, Faculty of Social Science, February , 1992)
[+]
[-]
Abstract:
For the analysis of productivity, capacity utilisation
and profitability the data relating to the manufacturing central
public sector enterprises in Kerala have been collected from the
published annual reports of the companies, public enterprises
surveys of Bureau of Public Enterprises (BPE), Economic Review of
State Planning Board (SPB) and statistical review of central
government enterprises by Centre for Monitoring Indian Economy
(CMIE). Primary data have been collected by conducting personal
interview with the high and middle level executives.
Multi-component reactions are effective in building complex molecules in a single step in a
minimum amount of time and with facile isolation procedures; they have high economy1–7
and thus have become a powerful synthetic strategy in recent years.8–10 The multicomponent
protocols are even more attractive when carried out in aqueous medium. Water
offers several benefits, including control over exothermicity, and the isolation of products
can be carried out by single phase separation technique. Pyranopyrazoles are a biologically
important class of heterocyclic compounds and in particular dihydropyrano[2,3-c]pyrazoles
play an essential role in promoting biological activity and represent an interesting template
in medicinal chemistry. Heterocyclic compounds bearing the 4-H pyran unit have received
much attention in recent years as they constitute important precursors for promising
drugs.11–13 Pyrano[2,3-c]pyrazoles exhibit analgesic,14 anti-cancer,15 anti-microbial and
anti-inflammatory16 activity. Furthermore dihydropyrano[2,3-c]pyrazoles show molluscidal
activity17,18 and are used in a screening kit for Chk 1 kinase inhibitor activity.19,20 They
also find applications as pharmaceutical ingredients and bio-degradable agrochemicals.21–29
Junek and Aigner30 first reported the synthesis of pyrano[2,3-c]pyrazole derivatives from
3-methyl-1-phenylpyrazolin-5-one and tetracyanoethylene in the presence of triethylamine.
Subsequently, a number of synthetic approaches such as the use of triethylamine,31
piperazine,32 piperidine,33 N-methylmorpholine in ethanol,34 microwave irradiation,35,36
solvent-free conditions,37–39 cyclodextrins (CDs),40 different bases in water,41 γ -alumina,42
and l-proline43 have been reported for the synthesis of 6-amino-4-alkyl/aryl-3-methyl-
2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles. Recently, tetraethylammonium bromide
(TEABr) has emerged as mild, water-tolerant, eco-friendly and inexpensive catalyst. To
the best of our knowledge, quaternary ammonium salts, more specifically TEABr, have notbeen used as catalysts for the synthesis of pyrano[2,3-c]pyrazoles, and we decided to investigate
the application of TEABr as a catalyst for the synthesis of a series of pyrazole-fused
pyran derivatives via multi-component reactions
Description:
Organic Preparations and Procedures International, 45:429–436, 2013
Santhosh Kumar, G; Deepthi, K V B L; Rama, Krishna Sharma V(er publications, December , 2013)
[+]
[-]
Abstract:
While channel coding is a standard method of improving a system’s energy efficiency in digital
communications, its practice does not extend to high-speed links. Increasing demands in network speeds
are placing a large burden on the energy efficiency of high-speed links and render the benefit of channel
coding for these systems a timely subject. The low error rates of interest and the presence of residual
intersymbol interference (ISI) caused by hardware constraints impede the analysis and simulation of coded
high-speed links. Focusing on the residual ISI and combined noise as the dominant error mechanisms, this
paper analyses error correlation through concepts of error region, channel signature, and correlation
distance. This framework provides a deeper insight into joint error behaviours in high-speed links, extends
the range of statistical simulation for coded high-speed links, and provides a case against the use of biased
Monte Carlo methods in this setting
Description:
International Journal of Enhanced Research in Science Technology & Engineering,
Vol. 2 Issue 12, December-2013, pp: (115-124)