Sony, George; Ajai, Kumar; Singh, R K; Nampoori, V P N(American Institute of Physics, 2009)
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Abstract:
The dynamics of plasma plume, formed by the laser-blow-off of multicomponent LiF-C thin film
under various ambient pressures ranging from high vacuum to argon pressure of 3 Torr, has been
studied using fast imaging technique. In vacuum, the plume has ellipsoidal shape. With the increase
in the ambient pressure, sharp plume boundary is developed showing a focusing-like confinement
in the lateral space behavior in the front end, which persists for long times. At higher ambient
pressure (> 10−1 Torr ), structures are developed in the plasma plume due to hydrodynamic
instability/turbulences.
Pramod, K V; Unnikrishnan, K(Academy Publisher, 2009)
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Abstract:
A feasible way of implementing a temporal
database is by mapping temporal data model onto a
conventional data model followed by a commercial database
management system. Even though extensions were proposed
to standard SQL for supporting temporal databases, such
proposals have not yet come across standardization
processes. This paper attempts to implement database
operators such as aggregates and universal quantifier for
temporal databases, implemented on top of relational
database systems, using currently available SQL standards.
Knoevenagel condensation between carbonyl compounds and active methylene compounds as well as three component Mannich reaction between aldehydes, ketones and amines proceeded smoothly in water with good to excellent yield and high selectivity in the presence of zero and first generation poly(amidoamine) (PAMAM) dendrimers. The products and the catalyst were separated by simple biphasic extraction. The catalyst was found to be reusable.
V P N Nampoori; Santhi Ani, Joseph; Misha, Hari; Mathew, S; Gaurav, Sharma; Soumya; Hadiya, V M; Radhakrishnan, P(Elsevier, Journal of Optics Communications, October 6, 2009)
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Abstract:
Dual beam mode-matched thermal lens method has been employed to measure the heat diffusion in
nanofluid of silver with various volumes of rhodamine 6G, both dispersed in water. The important observation
is an indication of temperature dependent diffusivity and that the overall heat diffusion is slower
in the chemically prepared Ag sol compared to that of water. The experimental results can be explained
assuming that Brownian motion is the main mechanism of heat transfer under the present experimental
conditions. Light induced aggregation of the nanoparticles can also result in an anomalous diffusion
behavior.
The thermal transport properties—thermal diffusivity, thermal conductivity and specific heat
capacity—of potassium selenate crystal have been measured through the successive phase
transitions, following the photo-pyroelectric thermal wave technique. The variation of thermal
conductivity with temperature through the incommensurate (IC) phase of this crystal is
measured. The enhancement in thermal conductivity in the IC phase is explained in terms of
heat conduction by phase modes, and the maxima in thermal conductivity during transitions is
due to enhancement in the phonon mean free path and the corresponding reduction in phonon
scattering. The anisotropy in thermal conductivity and its variation with temperature are
reported. The variation of the specific heat with temperature through the high temperature
structural transition at 745 K is measured, following the differential scanning calorimetric
method. By combining the results of photo-pyroelectric thermal wave methods and differential
scanning calorimetry, the variation of the specific heat capacity with temperature through all the
four phases of K2SeO4 is reported. The results are discussed in terms of phonon mode softening
during transitions and phonon scattering by phase modes in the IC phase.
Nithyaja, B; Jisha, V K; Tintu, R; Saramma, A V; V P N Nampoori(Laser Physics, 2009)
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Abstract:
The growth kinetics of an aerial bacterial colony on solid agar media was studied using laser
induced fluorescence technique. Fluorescence quenching of Rhodamin B by the bacterial colony was utilized
for the study. The lag phase, log phase, and stationary phase of growth curve of bacterial colony was identified
by measuring peak fluorescence intensity of dye doped bacterial colony.