116 resultados para CHRONOPOTENTIOMETRY WITH LINEAR CURRENT SCANNING
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
The production and quality of tomatoes has increased with the emergence of new genotypes and cropping systems such as hydroponics, however, there are few studies on the nutrition of plants. The objective was to evaluate the growth and motion of absorption of nutrients by Raisa tomato cultivar, grown in hydroponic system. The experimental design was randomized blocks with eight treatments consisting of the times of sampling: 15, 25, 35, 45, 55, 65, 75 and 85 days after transplanting (DAT) and five replications. The tomato seedlings were transplanted to pots of 8 dm(3) (on 31-03-2008), filled with the base substrate of coconut fiber, constantly irrigated with Hoagland and Arnon nutrient solution. During the experimental period and focuses on the development of plants and dry leaves, stems, fruits and roots. The dry matter accumulation of leaves and roots of tomato cultivar Raisa was relatively faster than the national stem and fruit, over cultivation, with predominance of dry fruits (45%) on the leaves (27%), the stem (24%) and roots (3%) at the end of the cycle. The accumulation of nutrients and micronutrients by the tomato cultivar Raisa was fit with linear increase throughout the cultivation, except for Mn which was quadratic. Most of the tomato nutritional requirement for nutrients was K, N and Ca and micronutrients was Fe, Zn and Mn.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Thaumastocoris peregrinus is a recently introduced invertebrate pest of non-native Eucalyptus plantations in the Southern Hemisphere. It was first reported from South Africa in 2003 and in Argentina in 2005. Since then, populations have grown explosively and it has attained an almost ubiquitous distribution over several regions in South Africa on 26 Eucalyptus species. Here we address three key questions regarding this invasion, namely whether only one species has been introduced, whether there were single or multiple introductions into South Africa and South America and what the source of the introduction might have been. To answer these questions, bar-coding using mitochondrial DNA (COI) sequence diversity was used to characterise the populations of this insect from Australia, Argentina, Brazil, South Africa and Uruguay. Analyses revealed three cryptic species in Australia, of which only T. peregrinus is represented in South Africa and South America. Thaumastocoris peregrinus populations contained eight haplotypes, with a pairwise nucleotide distance of 0.2-0.9% from seventeen locations in Australia. Three of these haplotypes are shared with populations in South America and South Africa, but the latter regions do not share haplotypes. These data, together with the current distribution of the haplotypes and the known direction of original spread in these regions, suggest that at least three distinct introductions of the insect occurred in South Africa and South America before 2005. The two most common haplotypes in Sydney, one of which was also found in Brisbane, are shared with the non-native regions. Sydney populations of T. peregrinus, which have regularly reached outbreak levels in recent years, might thus have served as source of these three distinct introductions into other regions of the Southern Hemisphere.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
This paper presents a novel single-phase high-power-factor (HPF) pulsewidth-modulated (PWM) boost rectifier featuring soft commutation of the active switches at zero current (ZC), It incorporates the most desirable properties of conventional PWM and soft-switching resonant techniques.The input current shaping is achieved with average current mode control and continuous inductor current mode.This new PWM converter provides ZC turn on and turn off of the active switches, and it is suitable for high-power applications employing insulated gate bipolar transistors (IGBT's),The principle of operation, the theoretical analysis, a design example, and experimental results from a laboratory prototype rated at 1600 W with 400-Vdc output voltage are presented. The measured efficiency and the power factor were 96.2% and 0.99%, respectively, with an input current total harmonic distortion (THD) equal to 3.94%, for an input voltage with THD equal to 3.8%, at rated load.
Resumo:
This paper is based on the development and experimental analysis of a DCM Boost interleaved converter suitable for application in traction systems of electrical vehicles pulled by electrical motors (Trolleybus), which are powered by urban DC or AC distribution networks. This front-end structure is capable of providing significant improvements in trolleybuses systems and in the urban distribution network costs, and efficiency. The architecture of proposed converter is composed by five boost power cells in interleaving connection, operating in discontinuous conduction mode. Furthermore, the converter can operate as AC-DC converter, or as DC-DC converter providing the proper DC output voltage range required by DC or AC adjustable speed drivers. Therefore, when supplied by single-phase AC distribution networks, and operating as AC-DC converter, it is capable to provide high power factor, reduced harmonic distortion in the input current, complying with the restrictions imposed by the IEC 61000-3-4 standards. The digital controller has been implemented using a low cost FPGA and developed totally using a hardware description language VHDL and fixed point arithmetic. Thus, two control strategies are evaluated considering the compliance with input current restrictions imposed by IEC 61000-3-4 standards, the regular PWM modulation and a current correction PWM modulation. In order to verify the feasibility and performance of the proposed system, experimental results from a 15 kW low power scale prototype are presented, operating in DC and AC conditions.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
The present research has proposed to estimate the genetic variation of growth traits and to estimate the expected gain by multi-effect index (MEI), in order to transform a Pinus caribaea var. caribaea progeny trial into a seedling seed orchard. The progeny trial was set up in 1989, in Selviria, MS, Brazil, using a 10 x 10 triple lattice design, with 99 progenies and a commercial control, with linear plots of ten plants, by the 3 x 3 m spacing between plants and rows. Total plant height, diameter at breast height (Dbh), wood volume, stem form, wood density at breast height, and survival were the evaluated quantitative traits. The trial was measured through 14, 15, and 16 years old. The 50% intensity of thinning at 14.3 years old was done. No significant was the genetic variation of different traits. Heritability estimates have presented low magnitude with low variation by the different ages. The application of MEI to DBH, at two years after thinning, resulted in higher gains than the selection of within and among progenies. The best selection strategy to obtain higher gains and to keep genetic diversity is to select until five plants per progenies.
Resumo:
OBJETIVO: Avaliar a evolução pós-operatória de pacientes com divertículo faringoesofagiano submetidos aos tratamentos cirúrgico e endoscópico. MÉTODOS: Foram analisados de maneira retrospectiva 36 pacientes com divertículo faringo-esofagiano atendidos no Hospital das Clínicas da Faculdade de Medicina de Botucatu - UNESP. Os pacientes foram distribuídos em dois grupos, na dependência do tratamento: grupo 1 (n=24) - diverticulectomia associada á miotomia do cricofaríngeo, através de cervicotomia esquerda; grupo 2 (n=12) - diverticulostomia endoscópica usando grampeador linear. RESULTADOS: A mortalidade operatória foi nula em ambos os grupos. Complicações precoces: grupo 1 - dois pacientes desenvolveram fistula cervical e outros dois, rouquidão; grupo 2 - sem complicações. Complicações tardias: grupo 1 - sem complicações: grupo 2: recidiva da disfagia em quatro pacientes (p=0,01). O seguimento médio foi 33 meses para o grupo 1 e 28 meses para o grupo 2. CONCLUSÃO: Os dois procedimentos foram eficazes na remissão da disfagia. O tratamento cirúrgico apresentou superioridade em relação ao endoscópico, com resolução da disfagia com um único procedimento. O tratamento endoscópico deve ser reservado para os mais idosos e portadores de comorbidades.