Artificial neural networks (ANNs) are relatively new computational tools that have found extensive utilization in solving many complex real-world problems. This paper describes how an ANN can be used to identify the spectral lines of elements. The spectral lines of Cadmium (Cd), Calcium (Ca), Iron (Fe), Lithium (Li), Mercury (Hg), Potassium (K) and Strontium (Sr) in the visible range are chosen for the investigation. One of the unique features of this technique is that it uses the whole spectrum in the visible range instead of individual spectral lines. The spectrum of a sample taken with a spectrometer contains both original peaks and spurious peaks. It is a tedious task to identify these peaks to determine the elements present in the sample. ANNs capability of retrieving original data from noisy spectrum is also explored in this paper. The importance of the need of sufficient data for training ANNs to get accurate results is also emphasized. Two networks are examined: one trained in all spectral lines and other with the persistent lines only. The network trained in all spectral lines is found to be superior in analyzing the spectrum even in a noisy environment.
Veena Gopalan, E; Al-Omari, I A; Malini, K A; Joy, P A; Sakthi Kumar, D; Yasuhiko, Yoshida; Anantaraman, M R(Elsevier, April , 2009)
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Abstract:
Mn1-xZnxFe2O4 nanoparticles (x=0-1) were synthesized by wet chemical co-precipitation techniques. X-ray diffraction, transmission electron microscopy and high-resolution transmission electron microscopy were effectively utilized to investigate the different structural parameters. The elemental analysis was conducted using energy-dispersive spectrum and inductively coupled plasma analysis. The magnetic properties such as magnetization and coercivity were measured using vibrating sample magnetometer. The observed magnetization values of the nanoparticles were found to be lower compared to the bulk counterpart. The magnetization showed a gradual decrease with zinc substitution except for a small increase from x=0.2 to 0.3. The Curie temperature was found to be enhanced in the case of ferrites in the nanoregime. The variation in lattice constant, reduced magnetization values, variation of magnetization with zinc substitution, the presence of a net magnetic moment for the zinc ferrite and the enhancement in Curie temperature in Mn1-xZnxFe2O4 all provide evidence to the existence of a metastable cation distribution together with possible surface effects at the nanoregime.
Raveendranath, U; Biju Kumar, S; Mathew, K T(IETE Technical Review, September , 1999)
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Abstract:
The performance of circular, rectangular and cross irises for the coupling of microwave power
to rectangular waveguide cavity resonators is discussed. For the measurement of complex
permittivity of materials using cavity perturbation techniques, rectangular cavities with high
Q-factors are required. Compared to the conventional rectangular and circular irises, the cross Iris
coupling structure provides very high loaded quality factor for all the resonant frequencies. The
proposes cross iris coupling structure enhances the accuracy of complex permittivity measurements.
Ethylene-propylene-diene rubber (EPDM) and isobutylene-isoprene rubber (IIR) were
compounded, precured to a low degree, and then were blended with natural rubber (NR).
The compounding ingredients for NR were then added and the final curing was done. NR/
EPDM and NR/IIR blends, prepared using this method, were found to possess much
improved mechanical properties as compared to their conventional counterparts. The optimum
precuring crosslink density that has to be given to the EPDM and IIR phases has
been determined.
Sulaiman,Pyroja; Binoy,Joseph; Paulose,C S(Department of Biotechnology, December 5, 2006)
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In the present study, serotonin 2C (5-HT2c) receptor binding parameters in the brainstem and cerebral cortex were investigated during
liver generation after partial hepatectomy (PH) and N-nitrosodiethylamine (NDEA) induced hepatic neoplasia in male Wistar rats. The
serotonin content increased significantly (p<0.01) in the cerebral cortex after PH and in NDEA induced hepatic neoplasia. Brain stem
serotonin content increased significantly (p<0.05) after PH and (p<0.001) in NDEA induced hepatic neoplasia. The number and affinity of
the 5-HT2c receptors in the crude synaptic membrane preparations of the brain stem showed a significant (p<0.001) increase after PH and in
NDEA induced hepatic neoplasia. The number and affinity of 5-HT2c receptors increased significantly (p<0.001) in NDEA induced hepatic
neoplasia in the crude synaptic membrane preparations of the cerebral cortex. There was a significant (p<0.01) increase in plasma
norepinephrine in PH and (p<0.001) in NDEA induced hepatic neoplasia, indicating sympathetic stimulation. Thus, our results suggest that
during active hepatocyte proliferation 5-HT2c receptor in the brain stem and cerebral cortex are up-regulated which in turn induce hepatocyte
proliferation mediated through sympathetic stimulation.
Renuka, T R; Remya, Robinson; Paulose, C S(Department of Biotechnology, November 2, 2005)
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Parasympathetic system plays an important
role in insulin secretion from the pancreas. Cholinergic
effect on pancreatic beta cells exerts primarily through
muscarinic receptors. In the present study we investigated
the specific role of muscarinic M1 and M3 receptors in
glucose induced insulin secretion from rat pancreatic islets
in vitro. The involvement of muscarinic receptors was
studied using the antagonist atropine. The role of muscarinic
MI and M3 receptor subtypes was studied using
subtype specific antagonists. Acetylcholine agonist, carbachol,
stimulated glucose induced insulin secretion at low
concentrations (10-8-10-5 M) with a maximum stimulation
at 10-7 M concentration. Carbachol-stimulated insulin
secretion was inhibited by atropine confirming the role of
muscarinic receptors in cholinergic induced insulin secretion.
Both M1 and M3 receptor antagonists blocked insulin
secretion induced by carbachol. The results show that M3
receptors are functionally more prominent at 20 mM glucose
concentration when compared to MI receptors. Our
studies suggest that muscarinic M1 and M3 receptors
function differentially regulate glucose induced insulin
secretion, which has clinical significance in glucose
homeostasis.
A comparative study of the effect of laser in inducing chromosomal
aberrations at 488 nm was done in Vicia faba L. (faba bean)
and Allium cepa L. (onion) with Argon ion laser (Spectra Physics Model
171). Seeds and bulbs of V. faba and A. cepa were subjected to laser irradiation
by 488 nm excitations from Argon ion laser source at power levels
200 and 400 mW with power densities 2.25 mW cm-2 and 4.49 mW
cm-2 and different exposure times ( 10, 20, 30 & 40 ..... tc) similar to the effect of other physical and chemical mutagens, laser caused a dose
dependent decrease in mitotic index and a rise in mitotic aberrations
when compared to the control . In both plant species, mutations were
observed in all stages of mitotic cell cycle . The total percentage of aberrations
was two fold higher at 400 mW than at 200 mW exposure.
Laser irradiation at wavelength 514 nm was used to study the effect, of lasers in inducing
chromosomal aberrations at mitosis. This study offers a new radiation system which could be used for the
induction of mutations. Results are compared with those obtained from studies using y-rays as irradiation
source.
Unnikrishna Pillai, P R; Padma, Nambisan; Nampoori, V P N; Vallabhan, C P G(HEREDITAS ( Beijing ), 1997)
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Abstract:
Laser irradiation at wavelength 514 nm was used to study the effect, of lasers in inducing
chromosomal aberrations at mitosis. This study offers a new radiation system which could be used for the
induction of mutations. Results are compared with those obtained from studies using y-rays as irradiation
source.
Balchand, A N; Jossia Joseph, K; Hareeshkumar, P V; Rajesh, G(Current Science, March , 2007)
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Abstract:
Time-series measurements from a moored data buoy
located in the Bay of Bengal captured signals of inertial
oscillation forced by the September 1997 cyclone. The
progressive vector diagram showed mean northeastward
current with well-defined clockwise circulation.
Spectral analysis exhibited inertial peak at 0.67 cpd
with blue shift and high rotary coefficient of –0.99, which
signifies strong circular inertial oscillation. The wind
and SST also exhibited spectral peak at inertial band
(0.69 cpd) with higher blue shift. The inertial amplitude
of 148.8 cm/s corresponding to a wind stress of 0.99 N/m2
and spectral peak near the local inertial frequency
(0.653 cpd) indicate that the transfer of momentum
was high.
Harilal, S S; Bindhu, C V; Nampoori, V P N; Vallabhan, C P G(American Institute of Physics, 1998)
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Abstract:
The effect of ambient gas on the dynamics of the plasma generated by laser ablation of a carbon target using 1.06 μm radiation from a Q-switched Nd:YAG laser has been investigated using a spectroscopic technique. The emission characteristics of the carbon plasma produced in argon, helium and air atmospheres are found to depend strongly on the nature and pressure of the surrounding gas. It has been observed that hotter and denser plasmas are formed in an argon atmosphere rather than in helium or air as an ambient.
The effect of residual cations in rare earth metal modified faujasite–Y zeolite has been monitored using magic angle spinning NMR spectral analysis and catalytic activity studies. The second metal ions being used are Na+, K+ and Mg+. From a comparison of the spectra of different samples, it is concluded that potassium and magnesium exchange causes a greater downfield shift in the 29Si NMR peaks. Also, lanthanum exchanged samples show migration behavior from large cages to small cages, which causes the redistribution of second counter cations. It is also observed that Mg2+ causes the most effective migration of lanthanum ions due to its greater charge. The prepared systems were effectively employed for the alkylation of benzene with 1-octene in the vapor phase. From the deactivation studies it is observed that the as-exchanged zeolites possess better stability towards reaction condition over the pure HFAU zeolite.
Suja, H; Deepa, C S; Sreeja Rani, K; Sugunan, S(Indian Journal of Chemistry, August , 2003)
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The present work attempts a systematic examination of the effect of sulphate content on the physico-chemical properties
and catalytic activity of sulphated zirconia and iron promoted sulphated zirconia systems. Sulphate content is estimated by
EDX analysis. The amount of sulphate incorporated has been found to influence the surface area, crystal structure and the
acid strength distribution. Ammonia TPD and adsorption studies using perylene have enabled the determination of surface
acidic properties. The results are supported by the thermodesorption studies using pyridine and 2,6-dimethylpyridine. The
catalytic activity towards benzoylation reaction has been correlated with the surface acidity of the systems.
Cyclohexanol decomposition activity of supported vanadia catalysts is ascribed to the high surface area, total acidity and interaction between supported vanadia and the amorphous support. Among the supported catalysts, the effect of vanadia over various wt% V2O5 (2–10) loading indicates that the catalyst comprising of 6 wt% V2O5 exhibits higher acidity and decomposition activity. Structural characterization of the catalysts has been done by techniques like energy dispersive X-ray analysis, X-ray diffraction and BET surface area. Acidity of the catalysts has been measured by temperature programmed desorption using ammonia as a probe molecule and the results have been correlated with the activity of catalysts.
Saou, Wen Su; Kin, Lu Wong(Microwave and Optical Technology Letters, September 20, 2005)
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novel design of at internal PIFA integrated with an
RF-shielding metal case for application in a clamshell or fielder-tvpe
mobile phone is presented. The integrated PIFA has a bent and tapered
radiating arm in order to easily fit in the casing of the clamshell mobile
phone as an internal antenna. The integrated PlEA can also provide a
wide operating bandwidth fir UM7S (1920-2170 MHz) operation. In
addition, for the clamshell mobile phone in either the talk or standby
condition, only a small effect on the operating bandwidth of the integrated
PIFA is obtained. The experimental results of the proposed design are presented
Balchand, A N; Chiranjivi Jayaram; Chacko, Neethu; Ajith Joseph, K(Ocean Science Journal, March 23, 2010)
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Abstract:
Increase in sea surface temperature with global
warming has an impact on coastal upwelling. Past two decades
(1988 to 2007) of satellite observed sea surface temperatures
and space borne scatterometer measured winds have provided
an insight into the dynamics of coastal upwelling in the
southeastern Arabian Sea, in the global warming scenario.
These high resolution data products have shown inconsistent
variability with a rapid rise in sea surface temperature between
1992 and 1998 and again from 2004 to 2007. The upwelling
indices derived from both sea surface temperature and wind have
shown that there is an increase in the intensity of upwelling
during the period 1998 to 2004 than the previous decade. These
indices have been modulated by the extreme climatic events
like El–Nino and Indian Ocean Dipole that happened during
1991–92 and 1997–98. A considerable drop in the intensity of
upwelling was observed concurrent with these events. Apart
from the impact of global warming on the upwelling, the
present study also provides an insight into spatial variability of
upwelling along the coast. Noticeable fact is that the intensity of
offshore Ekman transport off 8oN during the winter monsoon is
as high as that during the usual upwelling season in summer
monsoon. A drop in the meridional wind speed during the years
2005, 2006 and 2007 has resulted in extreme decrease in
upwelling though the zonal wind and the total wind magnitude
are a notch higher than the previous years. This decrease in
upwelling strength has resulted in reduced productivity too.
Jacob, Philip; Ginson, T J(International Frequency Sensor Association, December , 2008)
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Abstract:
Inter-digital capacitive electrodes working as electric field sensors have been developed for
touch panel applications. Evaluation circuits to convert variations in electric fields in such sensors into
computer compatible data are commercially available. We report development of an Interdigital
capacitive electrode working as a sensitive pressure sensor in the range 0-120 kPa. Essentially it is a
touch/proximity sensor converted into a pressure sensor with a suitable elastomer buffer medium
acting as the pressure transmitter. The performance of the sensor has been evaluated and reported.
Such sensors can be made very economical in comparison to existing pressure sensors. Moreover, they
are very convenient to be fabricated into sensor arrays involving a number of sensors for distributed
pressure sensing applications such as in biomedical systems.
Ram Mohan, H S; Santosh, K R; Sajith, V(American Geophysical Union, 2003)
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Abstract:
TRMM Microwave Imager (TMI) is reported to be a
useful sensor to measure the atmospheric and oceanic
parameters even in cloudy conditions. Vertically integrated
specific humidity, Total Precipitable Water (TPW) retrieved
from the water vapour absorption channel (22GHz.) along
with 10m wind speed and rain rate derived from TMI is
used to investigate the moisture variation over North Indian
Ocean. Intraseasonal Oscillations (ISO) of TPW during the
summer monsoon seasons 1998, 1999, and 2000 over North
Indian Ocean is explored using wavelet analysis. The
dominant waves in TPW during the monsoon periods and
the differences in ISO over Arabian Sea and Bay of Bengal
are investigated. The northward propagation of TPW
anomaly and its coherence with the coastal rainfall is also
studied. For the diagnostic study of heavy rainfall spells
over the west coast, the intrusion of TPW over the North
Arabian Sea is seen to be a useful tool.