• 한국전산유체공학회:학술대회논문집
• /
• 2008.08a
• /
• pp.40.2-40.2
• /
• 2008

• International Journal of Industrial Entomology and Biomaterials
• /
• v.13 no.2
• /
• pp.103-108
• /
• 2006

Efficacy of aqueous leaf extracts of medicinal plants viz., Eucalyptus globulus, Ocimum sanctum and Piper betle were evaluated against the hatching of eggs, mortality of nymphs and mortality and fecundity of adult mealy bugs (Maconellicoccus hirsutus Green) under in vitro conditions. Totally seven concentrations 1, 5, 10, 20, 50, 70 and 100 percent were tested against mealy bugs. The results revealed that with the increase in the concentration of extracts, there was a corresponding decrease in hatching, nymphal & adult mortality and fecundity in all the extracts tested. The hatching of eggs was minimum at 100 percent concentration in E. globulus (20.00%) followed by O. sanctum (30.42%) and P. betle (36.06%) over control (96.73%). The growth and development of nymphs and adults were adversely affected after the treatment. The nymphs did not attain the adult stage and there was total mortality of nymphs in different treatments. The duration of nymphal stage was reduced by 2-10 days in E. globulus, 1-7 days in O. sanctum and 1-2days P. betle at higher concentrations. However, at lower concentrations it was prolonged by 2-4 days in all the three extracts. At lower concentrations the mortality of adults was on par with the control. Similarly the adult duration was also reduced by 3-4 days at 100 percent concentration and prolonged by 5-6 days at lower concentrations in all the extracts. With the increase in concentrations of the extracts there was decrease in the fecundity of eggs. Thus, the leaf extracts of E. globulus was found to be most effective followed by O. sanctum and P. betle against mealy bugs.

• 한국전산유체공학회:학술대회논문집
• /
• 2008.08a
• /
• pp.41.2-41.2
• /
• 2008

• 한국전산유체공학회:학술대회논문집
• /
• 2008.08a
• /
• pp.72.1-72.1
• /
• 2008

• 한국전산유체공학회:학술대회논문집
• /
• 2008.08a
• /
• pp.72.2-72.2
• /
• 2008

• Geomechanics and Engineering
• /
• v.1 no.3
• /
• pp.219-239
• /
• 2009

Vertical vibration tests were conducted using model footings of different size and mass resting on the surface of finite sand layer with different height to width ratios and underlain by either rigid concrete base or natural red-earth base. A comparative study of the ratio of predicted and observed natural frequency ratio of the finite sand stratum was made using the calculated values of equivalent stiffness suggested by Gazetas (1983) and Baidya and Muralikrishna (2001). Comparison of results between model footings resting on finite sand stratum underlain by the rigid concrete base and the natural red-earth base showed that, the presence of a finite base of higher rigidity increases the resonant frequency significantly. With increase in H/B ratio beyond 2.0, the influence of both the rigid concrete and natural red-earth base decreases. Increase in the contact area of the footing increases the resonant frequency of the model footings resting on finite sand stratum underlain by both the types of finite bases. Both the predicted and the observed resonant frequency ratio decreases with increase in force rating and height to width ratio for a given series of model footing.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.10
• /
• pp.3046-3054
• /
• 2013

Synthesis of Carbon Nanotube bundles has been achieved by simple and economical solvothermal procedure at very low temperature of $180^{\circ}C$. The product yield obtained was about 70-75%. The optimization of reaction conditions for an efficient synthesis of CNTs has been presented. The CNTs are obtained by reduction of hexachlorobenzene in the presence of Na/Ni in cyclohexane. The X-ray diffraction, Fourier transform infrared and Raman spectral studies have inferred us the graphene structure of the products. The CNTs formed as the bundles were viewed on scanning electron microscope, transmission electron microscope and high-resolution transmission electron microscope. These are the multiwalled CNTs with outer diameter of 5-10 nm, the inner diameter 2-4 nm and cross sectional diameter up to 5 nm. Brunauer-Emmett-Teller (BET) based $N_2$ gas adsorption studies have been made to obtain BET surface area and $H_2$ storage capacity. Effect of the experimental variables such as reaction temperature, amount of catalyst and the amount of carbon source were investigated. It is found that they affect significantly on the product nature and yield.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.11
• /
• pp.3544-3550
• /
• 2012

Cetrizine dihydrochloride (CTZH) is widely used as an anti-allergic drug. Sodium N-bromo-p-toluenesulfonamide or bromamine-T (BAT) is the bromine analogue of chloramine-T (CAT) and is found to be a better oxidizing agent than CAT. In the present research, the kinetics of oxidation of CTZH with BAT in acid and alkaline media was studied at 313 K. The experimental rate laws obtained are: -d[BAT]/dt=$k[BAT][CTZH]^{0.80}[H^+]^{-0.48}$ in acid medium and -d[BAT]/dt=$k[BAT][CTZH]^{0.48}[OH^-]^{0.52}[PTS]^{-0.40}$ in alkaline medium where PTS is p-toluenesulfonamide. Activation parameters and reaction constants were evaluated. The solvent isotope effect was studied using $D_2O$. The dielectric effect is positive. The stoichiometry of the reaction was found to be 1:1 and the oxidation products were identified as 4-chlorobenzophenone and (2-piperazin-1-yl-ethoxy)-acetic acid in both media. The rate of oxidation of CTZH is faster in acid medium. Suitable mechanisms and related rate laws have been worked out.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.99-106
• /
• 2013

Polyaniline-yttrium trioxide (PAni-$Y_2O_3$) composites were synthesized by the in-situ polymerization of aniline in the presence of $Y_2O_3$ The composite formation and structural changes in these composites were investigated by X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The direct current (DC) electrical conductivity of the order of $0.51{\times}10^{-2}\;S\;cm^{-1}-0.283\;S\;cm^{-1}$ in the temperature range 300 K-473 K indicates semiconducting behavior of the composites. Room temperature AC conductivity and dielectric response of the composites were studied in the frequency range of 10 Hz to 1 MHz. The variation of AC conductivity with frequency obeyed the power law, which decreased with increasing weight percentage (wt %) of $Y_2O_3$. Studies on dielectric properties shows the relaxation contribution coupled by electrode polarization effect. The dielectric constant and dielectric loss in these composites depend on the content of $Y_2O_3$ with a percolation threshold at 20 wt % of $Y_2O_3$ in PAni. Electromagnetic interference shielding effectiveness (EMI SE) of the composites in the frequency range 100 Hz to 2 GHz was in the practically useful range of -12.2 dB to -17.2 dB. The observed electrical and shielding properties were attributed to the interaction of $Y_2O_3$ particles with the PAni molecular chains.

• Structural Engineering and Mechanics
• /
• v.36 no.5
• /
• pp.625-642
• /
• 2010

The Integrated Force Method (IFM) is a novel matrix formulation developed for analyzing the civil, mechanical and aerospace engineering structures. In this method all independent/internal forces are treated as unknown variables which are calculated by simultaneously imposing equations of equilibrium and compatibility conditions. This paper presents a new 12-node serendipity quadrilateral plate bending element MQP12 for the analysis of thin and thick plate problems using IFM. The Mindlin-Reissner plate theory has been employed in the formulation which accounts the effect of shear deformation. The performance of this new element with respect to accuracy and convergence is studied by analyzing many standard benchmark plate bending problems. The results of the new element MQP12 are compared with those of displacement-based 12-node plate bending elements available in the literature. The results are also compared with exact solutions. The new element MQP12 is free from shear locking and performs excellent for both thin and moderately thick plate bending situations.