Enraizamento de estacas de crisântemo [Dendranthema morifolium (RAMAT.) TZVELEV] tratadas com ácido indolbutírico veiculado em talco

The present study was carried out in order to evaluate chrysanthemum cuttings rooting quality when treated with indolebutyric acid (IBA) by the powder method, at several doses, and transplanted at three different ages. Yellow Reagan 622 chrysanthemum cuttings were treated with IBA at doses of 0, 500, 1000 and 2000 ppm. Evaluations of the visual aspect and dry matter weight observations were carried out on the 10th, 12th and 14th rooting days. In addition, plants which received the same IBA treatments were transplanted after 10, 12 and 14 days of rooting, to the plant development site, where they remained until flower harvest. Under these conditions, plant lenght and dry matter weight were evaluated. Data analysis allows to conclude that: a) Chrysanthemum cutting rooting is dependent on the doses of IBA and on transplanting age. b) However, the best results are obtained with 1000 ppm of IBA. On the first stage, transplanting at the 14th day is the most effective; however, the best plant development is obtained at the 12th transplanting day.O presente trabalho foi realizado com o propósito de avaliar a qualidade do enraizamento de estacas de crisântemo tratadas com ácido indolbutírico (IBA) veiculado em talco sob diversas dosagens, transplantadas em três idades diferentes e seus efeitos posteriores no desenvolvimento de plantas. Estacas de crisântemo do cultivar Yellow Reagan 622 foram tratadas com IBA nas dosagens de 0, 500, 1000 e 2000 ppm. Foram efetuadas avaliações do aspecto visual e do peso de matéria seca das estacas enraizadas com 10, 12 e 14 dias de enraizamento. Adicionalmente, foram transplantadas mudas, que receberam os mesmos tratamentos com IBA, após 10, 12 e 14 dias de enraizamento, para o local de desenvolvimento de plantas, onde permaneceram até o momento de colheita das flores. Nestas condições foram feitas avaliações do comprimento e do peso de matéria seca das plantas. A análise dos dados e a interpretação dos resultados do presente trabalho permitem concluir que: a) o enraizamento de estacas de crisântemo é dependente da dosagem de IBA e das idades de transplante. b) Melhores resultados são observados nas dosagens próximas a 1000 ppm de IBA. c) Na primeira fase o transplante aos 14 dias é mais eficiente, porém, com o desenvolvimento das plantas, o transplante aos 12 dias é aquele que apresenta melhores resultados

An experimental application of aeroacoustic time-reversal to the Aeolian tone

This paper presents an experimental application of the aeroacoustic time-reversal (TR) source localization technique for studying flow-induced noise problems and compares the TR results with those obtained using conventional beamforming (CB). Experiments were conducted in an anechoic wind tunnel for the benchmark test-case of a full-span circular cylinder located in subsonic cross-flow wherein the far-field acoustic pressure was sampled using two line arrays (LAs) of microphones located above and below the cylinder. The source map obtained using the signals recorded at the two LAs without modeling the reflective surfaces of the contraction-outlet and cylinder during TR simulations revealed the lift-dipole nature of aeroacoustic source generated at the Aeolian tone; however, it indicates an error of 3/20 of Aeolian tone wavelength in the predicted location. Modeling the reflective contraction-outlet during TR was shown to improve the focal-resolution of the source and reduce side-lobe levels, especially in the low-frequency range. The experimental TR results were shown to be comparable to (a) the simulation results of an idealized dipole at the cylinder location in wind-tunnel flow and (b) that obtained by monopole and dipole CB, thereby demonstrating the suitability of TR method as a diagnostic tool to analyze flow-induced noise generation mechanism.A. Mimani, Z. Prime, D. J. Moreau and C. J. Doola

Enhanced lithium-ion transport in PEG-based composite polymer electrolyte with Mn<SUB>0. 03</SUB>Zn<SUB>0.97</SUB>Al<SUB>2</SUB>O<SUB>4</SUB> nanoparticles

The ion conduction and thermal properties of composite solid polymer electrolyte (SPE) comprising Poly(ethylene) Glycol (PEG, mol wt. 2000), lithium perchlorate (LiClO<SUB>4</SUB>) and insulating Mn<SUB>0.03</SUB>Zn<SUB>0.97</SUB>Al<SUB>2</SUB>O<SUB>4 </SUB>nanoparticle fillers were studied by complex impedance analysis and DSC techniques. The average size of the nanoparticles was determined by powder X-ray diffraction (XRD) using Scherrer's equation and was found to be~8 nm. The same was also determined by TEM imaging and found to be~12 nm. The glass transition temperature T<SUB>g</SUB>, as measured by differential scanning calorimeter (DSC), showed a minimum at 5 mol% of nanoparticles. Fractional crystallinity was determined using DSC. NMR was used to determine crystallinity of a pure PEG sample, which was then used as the standard. Fractional crystallinity X<SUB>c</SUB> was the lowest for 5 mol% and beyond. The ionic conductivity of the composite polymer electrolyte containing 5 mol% Mn<SUB>0.03</SUB>Zn<SUB>0.97</SUB>Al<SUB>2</SUB>O<SUB>4</SUB> nanoparticles was found to be 1.82&#215; 10<SUP>-5</SUP> S/cm, while for the pristine one, it was 7.27×10<SUP>-7</SUP> S/cm at room temperature. As a function of nanoparticle content, conductivity was observed to go through two maxima, one at around 5 mol% and another shallower one at around 12 mol%. The temperature dependence of conductivity could be divided into two regions, one consistent with Arrhenius behaviour and the other with VTF. We conclude that the enhancement of ionic conductivity on the addition of Mn<SUB>0.03</SUB>Zn<SUB>0.97</SUB>Al<SUB>2</SUB>O<SUB>4</SUB> nanoparticles is a result of reduction in both the T<SUB>g</SUB> and the crystallinity

Combustion synthesis of nanostructured barium titanate

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