Produção de fitomassa, teor e produtividade do óleo essencial de Baccharis dracunculifolia DC. em função da adubação orgânica

Objetivou-se avaliar a produção de fitomassa, teor e produtividade do óleo essencial de Baccharis dracuculifolia DC., em função de doses de adubo orgânico, e foram utilizadas mudas produzidas por semente, e mantidas sob sombrite pelo período de 84 dias até serem transplantadas para o campo, no espaçamento de 1,0 x 1,0 m, com irrigação por gotejamento. O delineamento estatístico utilizado foi em blocos ao acaso, com quatro repetições, e as doses de composto orgânico foram: 0, 10, 20, 30, 40 e 50 t ha-1. Foi realizada uma colheita, aos 150 dias após o transplante das mudas. O óleo essencial foi extraído por hidrodestilação e analisado em cromatógrafo a gás acoplado a espectrômetro de massas (Shimadzu, QP-5000). Todos os resultados foram submetidos à análise de variância pelo teste F seguido da análise de regressão e o teste Tukey para os dados: massa seca útil da parte aérea, teor e produtividade do óleo essencial. Para as variáveis massa seca total e massa seca útil da parte aérea, as dosagens estudadas influenciaram as plantas, que apresentaram os melhores resultados na dose 50 t ha-1. Para teor de óleo não houve influência significativa para as dosagens estudadas, porém a dose 30 t ha-1 apresentou o melhor resultado. Entretanto para a produtividade do óleo essencial, as dosagens estudadas influenciaram as plantas, que na dosagem 30 t ha-1 obtiveram os melhores resultados.The objective was to evaluate the characteristics of the Baccharis dracunculifolia DC., depending on levels of organic fertilizer, and seedlings were used B. dracunculifolia produced by seed, and kept under shade for a period of 84 days before being transplanted to the field, spaced 1.0 x 1.0 m, with drip irrigation. The experimental design was randomized blocks with four replications, and doses of organic compost, 0, 10, 20, 30, 40 and 50 t ha-1. We performed a harvest, 150 days after transplanting. The essential oil was extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometer (Shimadzu, QP-5000). All results were submitted to analysis of variance F test followed by regression analysis and Tukey test for the data: useful dry mass of shoots, content of essential and productivity of essential oil. For the variables total dry mass and dry mass of shoots useful, the doses studied influenced the plants, which showed the best results at a dose 50 t ha-1. For content of essential oil no significant influence was verified on the doses studied, but the dose 30 t ha -1 showed the best result. However the productivity of the essential oil, the doses studied influenced the plants, which in dose 30 t ha-1 obtained the best results

Micro-generation with solar energy: Power qualtity and impact on a rural low-voltage grid

In recent years the grid connected photovoltaic (PV) micro-generation facilities in individual homes has increased due to the adopted governmental policies and the industry attention. The power feed-in of PV generation in rural low-voltage grid can influence the power quality and the facility operation and reliability. This paper presents the results of a power quality analysis of a real PV generation facility connected to a rural low-voltage grid. The voltage fluctuations and the voltage harmonic content are observed and a statistical analysis and discussion are performed. The main achievements of the work are the statement of the disturbances imposed to the grid and its consequences to the technical and economic viability of the PV system.info:eu-repo/semantics/publishedVersio

Producing hybrid pultruded structural products based on preforms

Hybrid pultrusion is a process that can be used to fabricate different products, enclosing distinct techniques and materials. Its development comes from the need to obtain properties' reinforcement of the structural profiles obtained by pultrusion, allowing its application into specific situations, such as thermal or acoustic insulation or to increase the product's moment of inertia, without having a proportional weight increase. In this work was developed based on a novel idea of manufacturing pultruded pipes around preforms of good thermal and/or acoustic insulator materials, such as cork and polyurethane foam. However, the same terminology was already used to describe fabrication techniques in which pultruded structural profiles were combined with concrete structures in order to increase the mechanical and/or flexural resistance, diminishing the total weight. Nevertheless, no industrial equipment is currently available on the market regarding the production of hybrid pultruded products based on preforms. Thus, novel equipment has been designed to provide a good connection with a conventional existing pultrusion machine, allowing the production of pultruded pipes that involve cork and polyurethane foam preforms in a continuous way. The equipment has been developed and tested, enable obtaining hybrid pultruded products that can be applied in several situations where flexural strength, acoustic or thermal insulation must be improved relatively to conventional pultruded products, broadening the market for this type of structural products. The manufacturing equipment is prepared to work without permanent workers, needing to be refilled every 60 min and showed to be competitive, being able to add value to the conventional profiles already on the market. Preliminary tests were carried out showing clearly the improvement of the mechanical strength, thermal insulation and acoustic insulation capacities.info:eu-repo/semantics/publishedVersio

Distribution of the stx1 and stx2 genes in Escherichia coli isolated from milk cattle according to season, age, and production scale in southwestern region of Goiás, Brazil

ABSTRACT This study determined the distribution of stx1 and stx2 genes in Escherichia coli isolated from dairy herds with regard to animal age, season, and farm production-scale, and analyzed the phylogenetic distribution of the groups A, B1, B2, and D of 276 isolates of bovine feces Shiga toxin-producing E. coli (STEC). The stx1 profile was the most common, detected in 20.4% (202/990) of the isolates, followed by stx2 (4.54%, 45/990) and stx1+stx2 (2.92%, 29/990). The stx1 gene was detected more frequently in calves than in adult animals. In the dry season (winter), the presence of stx1+stx2 profile in cattle feces was higher than in the rainy season (summer), while no significant changes were observed between seasons for the stx1 and stx2 profiles. The most predominant phylogenetic groups in adult animals were B1, A, and D, while groups A and B1 prevailed in calves. Our data highlight the importance of identifying STEC reservoirs, since 7.5% of the tested isolates were positive for stx2, the main profile responsible for the hemolytic-uremic syndrome (HUS). Moreover, these microorganisms are adapted to survive even in hostile environments and can contaminate the food production chain, posing a significant risk to consumers of animal products.</div