Eficiência de uso de boro no crescimento de clones de eucalipto em vasos

This paper evaluated the critical level, responsivity and boron use effciency on growth and the biomass production in six Eucalyptus grandis x Eucalyptus urophylla clones (Ca, Cb, Cc, Cd, Ce and Cf). An experiment was carried out in pots containing ground silicon, under greenhouse conditions using four boron rates per solution (0; 0.135; 0.27; 0.54 mg L -1 of B). The treatments were combined in a randomized block experimental design in a 4 × 6 factorial scheme with three replications. Plant height, stem diameter, dry matter production in the shoots of the plant and boron use effciency in the leaves, stem and total dry matter at the 8th month of age were evaluated. Due to boron fertilization, growth and shoot biomass were observed in the Eucalyptus plants after 240 days of being planted in pots. The increases in growth and biomass were 35 to 54% and 21 to 64%, respectively. The boron rates that promoted major growth of the plants were 0.33 to 0.44 mg L -1 of B and in this range the most effcient clone for dry matter production of leaves was Cf and the least effcient one to stem biomass production and the shoot biomass was Cd, no signifcant differences among other clones were observed. The critical level of boron in solution was 0.09 to 0.24 mg L -1 of B in the growth of the plants.

Grinding of hardened steels using optimized cooling

Grinding - the final machining process of a workpiece - requires large amounts of cutting fluids for the lubrication, cooling and removal of chips. These fluids are highly aggressive to the environment. With the technological advances of recent years, the worldwide trend is to produce increasingly sophisticated components with very strict geometric and dimensional tolerances, good surface finish, at low costs, and particularly without damaging the environment. The latter requirement can be achieved by recycling cutting fluids, which is a costly solution, or by drastically reducing the amount of cutting fluids employed in the grinding process. This alternative was investigated here by varying the plunge velocity in the plunge cylindrical grinding of ABNT D6 steel, rationalizing the application of two cutting fluids and using a superabrasive CBN (cubic boron nitride) grinding wheel with vitrified binder to evaluate the output parameters of tangential cutting force, acoustic emission, roughness, roundness, tool wear, residual stress and surface integrity, using scanning electron microscopy (SEM) to examine the test specimens. The performance of the cutting fluid, grinding wheel and plunge velocity were analyzed to identify the best machining conditions which allowed for a reduction of the cutting fluid volume, reducing the machining time without impairing the geometric and dimensional parameters, and the surface finish and integrity of the machined components.

Crescimento de cultivares de mamoneira em função da aplicação de boro, durante a formação de mudas

It was objectified to quantify the initial growth of varieties of castor bean with boron fertilization. Had been tested to cultivate they AL-Guarani, Mirante 10 and Nordestina to the doses of 0; 0.25; 0.50; 0.75 and 1.0 mg kg -1 of B in controlled environment of greenhouse in the Sector of Cafeicultura of the Department of Agriculture of the UFLA. The characteristics valued were: height of plants, length of roots, leaf number, diameter of stem, mass of dry substance (MS) of leafs, of stem, the root and total. To cultivate Mirante 10 it was the one that got minor growth of the system of root. For leaf number to cultivate AL-Guarani it was superior to Mirante 10 and Nordestina. Also to cultivate better AL-Guarani if it detached how much to the production of total mass of MS, while to cultivate Mirante 10 produced more mass of MS than Nordestina.

Respostas de clones de Eucalyptus grandis e E. grandis x E. urophylla à supressão de boro

The present work had as objective the study of clones of Eucalyptus grandis and E. grandis × E. urophylla under boron suppression on growth in height and diameter, development of symptoms of deficiency, boron content in leaf and polyols production. Plants were cultivated in pots with quartz in a greenhouse using two levels of boron per solution (0 and 0.5 mg L-1 of B). The 32 treatments followed a factorial scheme: 16 × 2 -16 clones and two doses of boron in a randomized block experimental design, with fve repetitions, totaling 160 plots. Plants were evaluated weekly for deficiency symptoms and monthly for height, stem diameter and leaf content of boron in different plant parts. The content of polyols was measured in two occasions: at 162 days and 192 days after starting the experiment. Decrease of growth and quick development of deficiency symptoms 40 days after boron suppression were observed, as well as a decrease of polyols synthesis. Foliar analysis, with boron supplement, resulted in the presence of mannitol and sorbitol in high enough concentration so that the evaluated plants could be considered rich in those polyols. Under boron suppression, boron levels in different portions of branches and stems of plants, as well as the presence of mannitol and sorbitol, indicated a conditional mobility of boron in Eucalyptus.

When small is different: The case of membranes inside tubes

Recently, classical elasticity theory for thin sheets was used to demonstrate the existence of a universal structural behavior describing the confinement of sheets inside cylindrical tubes. However, this kind of formalism was derived to describe macroscopic systems. A natural question is whether this behavior still holds at nanoscale. In this work, we have investigated through molecular dynamics simulations the structural behavior of graphene and boron nitride single layers confined into nanotubes. Our results show that the class of universality observed at macroscale is no longer observed at nanoscale. The origin of this discrepancy is addressed in terms of the relative importance of forces and energies at macro and nano scales. © 2012 Materials Research Society.

Exportação de nutrientes em plantas de jambu, sob diferentes adubações

The jambu is a broad vegetable consumption in Northern Brazil, especially in Pará, known by the jambu and other common names is native to the Amazon region has been used and cultivated for culinary and also recently in natural medicines by their chemical properties, attributed to the spilanthol compound. Knowing the amount of nutrient uptake in plants, especially at the taken, it is important to evaluate the removal of nutrients necessary for economic fertilizer recommendations. So the goal of this project was to determine the accumulation of nutrients in plants of jambu (leaf and inflorescence) under different fertilizations. The experiment was conducted at São Manuel Experimental Farm UNESP. The statistical was arranged in the randomized block design, in a 2 x 6 factorial scheme, two sources of fertilizers (organic and mineral) and six doses of nitrogen, with four replications. We evaluated the macronutrients of accumulation N, P, K, Ca, Mg, S and micronutrients of accumulation B, Cu, Fe and Zn in leaves and inflorescence. The plants responded more jambu nutrients of translocation phosphorus (P), magnesium (Mg), sulfhur (S), boron (B), copper (Cu) and iron (Fe) in the inflorescences and phosphorus (P), calcium (Ca), manganese (Mg), sulfur (S), boron (B), copper (Cu) and iron (Fe) in leaves to organic fertilization demonstrating the effectiveness of using this source of fertilizer nutrients indicating that this was a defining characteristic in response to the accumulation of nutrients in the leaves and inflorescences jambu. Plants jambu are more responsive to fertilizer for the mineral of translocation nitrogen (N) and manganese (Mn) for both the sheet and for the inflorescences of plants jambu.

Influence of Agroforestry and Traditional Management of Maize (Zea mays L.) on Soil Fertility

The aim of the work was to evaluate soil nutrient concentration at 0-5, 5-10, and 10-20 cm in maize (Zea mays L.) grown in sequence with black oats (Avena strigosa Schreb.) under Leucaena diversifolia alley cropping agroforestry system (AFS) and traditional management system/sole crop (without trees-TS), following a randomized block design. The experiment was carried out at the Brazilian Association of Biodynamic Agriculture, in Botucatu, São Paulo, Brazil. The treatments were: control (C), chemical fertilizer (F), biomass of L. diversifolia alley cropping (B), and biomass of L. diversifolia alley cropping + chemical fertilizer (B+F). After 2 yr, it was observed that pH, organic matter, and nutrient content had a tendency to show higher values in the treatments biomass+fertilizer, biomass, and fertilizer application, in both systems. Higher values in pH, organic matter, phosphorus, potassium, calcium, magnesium, sum of bases, cation exchange capacity, percentage base saturation, boron, copper, and manganese tended to occur in the agroforestry system. © 2013 Copyright Taylor and Francis Group, LLC.

Determination of Total Nitrosamines in Vegetables Cultivated Organic and Conventional Using Diamond Electrode

Vegetables were analyzed for total N-nitrosamines (NAs) and the influence of disinfection processes was assessed. Differences in NAs found in cabbage, spinach, and broccoli were determined by square wave voltammetry using a boron-doped diamond electrode. Analysis of samples showed that all samples contained detectable levels of NAs but the results indicated that organic contained less than conventionally grown products. The sum of the total NAs was higher in the cabbage samples, ranging between 2.8-3.1 ppb and lower in broccoli samples at 0.2-1.1 ppb. The method described is simple, rapid, selective, and sensitive. The results suggested that the disinfection process affects the level of NAs, in this manner affecting the level of human exposure to NAs. © 2012 Springer Science+Business Media New York.

Comportamento de milho (Zea Mays L.) e propriedades físicas do solo, no sistema plantio direto, em resposta a aplicação de fertilizante organomineral

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da disponibilidade de boro em um latossolo de Mato Grosso/MT

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Maturação induzida, alterações fisiológicas, produtividade e qualidade tecnológica da cana-de-açúcar (Saccharum officinarum L.)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da qualidade de mourões de várias espécies de Eucalyptus spp. tratados pelo método de substituição de seiva

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Análise do processo de torneamento a quente auxiliado por resistência elétrica de quartzo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rendimento, qualidade e conservação pós-colheita de cenoura (Daucus carota L.), sob cultivo biodinâmico, em função dos ritmos lunares

Pós-graduação em Agronomia (Horticultura) - FCA

Produção, qualidade e conservação pós-colheita de mandioquinha-salsa (Arracacia xanthorrhiza Bancroft) sob adubações mineral, orgânica e biodinâmica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)