Amostragem de sólidos em espectrometria de absorção atômica de fonte contínua com alta resolução: análise de plantas medicinais

Pós-graduação em Química - IQ

Absorção de nutrientes e alterações químicas em Latossolos cultivados com plantas de cobertura em rotação com soja e milho

The effects on soil chemical properties brought about by cover crops vary considerably. This study was conducted to evaluate nutrient uptake by five cover crops used for grain, seed and forage production at different seed densities per hectare, as well as uptake by spontaneous vegetation, and their effect on the chemical properties of two Oxisols when grown in rotation with soybean and corn. The experiments were set up in Votuporanga, SP, Brazil and Selvíria, MS, Brazil in March 2008 after conventional soil tillage. A randomized complete block experimental design was used with four replications with the following cover crops at different seed densities: Sorghum bicolor at 6, 7 and 8 kg ha-1; Pennisetum americanum at 10, 15 and 20 kg ha-1; Sorghum sudanense at 12, 15 and 18 kg ha-1; hybrid of Sorghum bicolor with Sorghum sudanense at 8, 9 and 10 kg ha-1; and Urochloa ruziziensis at 8, 12 and 16 kg ha-1. We also used a spontaneous vegetation control. After management of the cover crops, in the first year of study, soybean was sown in no-tillage system and, in the second year, corn was sown, also in a no-tillage system. We evaluated the dry matter yield of different cover crops, nutrient uptake by the cover crops, and the chemical changes in the soil. It was found that in clayey soils with high aluminum content, as in Selvíria, sudan grass at a seed density of 18 kg ha-1, and sorghum at a seed density of 6 kg ha-1, in combination with liming, contributed to reduction of aluminum content and high potential acidity and an increase in base saturation. The different seed densities of each cover crop did not affect the dry matter yield of the cover crop itself, but affected nitrogen uptake of the hybrid Sorghum bicolor with Sorghum sudanense at a seed density of 10 kg ha-1, with lower uptake than at a seed density of 8 kg ha-1. Seed density also affected the organic matter content in the soil with sudan grass, with the seed density of 15 kg ha-1 providing more organic matter content than a seed density of 18 kg ha-1.

Absorção de nutrientes em cultivares de gérbera cultivada em vaso

The analysis of the uptake of nutrients is important for understanding the nutritional requirements of a cultivar during its development and identifies periods of increased demand, which allows scheduling fertigation. Nevertheless, the information is limited for gerbera. Thus, the present study was conducted to determine the uptake of potted gerbera cultivars Cherry and Red conducted in substrate in a crop cycle in the period August-October 2008. The experiment was carried out in a greenhouse in a randomized block split plot with four replications. The plots were composed by cultivars and subplots by dates of collection. During the development of the plants, the content and accumulation of macro and micronutrients was assessed in plant tissue of the shoots. The macronutrients were accumulated in the following order: K>N>Ca>Mg>P>S (524, 334, 119, 47, 42, 21 mg plant-1). The micronutrients were accumulated in the following order: Fe>Mn>B>Zn>Cu (7897, 1505, 801, 384,63 µg plant-1). The reproductive was the period of greatest uptake of nutrients, except for Fe.

Determinação de 'SB' e 'PB' em embalagens de poli(tereftalato) de etileno (PET) por espectrometria de absorção atômica com fonte contínua e de alta resolução em forno de grafite empregando amostragem direta de sólidos

Pós-graduação em Química - IQ

Sensores ópticos para quantificação de sulfeto de hidrogênio em matrizes gasosas por espectrometria de floorescênica do UV-visível e espectroscopia de absorção no infravermelho: João Flávio da Silveira Petruci. -

Pós-graduação em Química - IQ

Desenvolvimento radicular e aéreo, nutrição e eficiência de absorção de macronutrientes e zinco por cultivares de arroz de terras altas afetadas pela adubação fosfatada

In Brazil, phosphorus availability is one factor that that more limit yield of upland rice under rainfed system. Then, better understanding of cultivars development at phosphorus soil fertilization is very important in the production systems making this more sustainable. The objective was to evaluate the influence of phosphorus doses applied to the soil over the root length, root and shoot dry matter, concentration and content of macronutrient and zinc in shoot and root as well as the efficiency of nutrient uptake per meter root of upland cultivars of intermediate and modern groups. The experiment was carried out in greenhouse conditions in a completely randomized design in factorial scheme 4 x 4. Treatments were four levels of P fertilization applied at the soil (0, 50, 100 and 200 mg dm(-3) of P) and four upland rice cultivars (Maravilha - modern group, IAC-201, IAC-202 and Carajas - intermediate group). There is increase in phosphorus availability in the soil with increasing levels of P fertilization. Under low phosphorus availability, cultivars of the intermediate group have better shoots and root system development in relation to the modern cultivar group. Level of phosphorus affected nutrients contents in shoots and root system of upland rice cultivars. The increasing phosphorus fertilization increased uptake of nutrients per meter of root; and although under higher phosphorus availability there was a greater root growth, in low phosphorus availability root growth was greater at the expense of shoot growth.

Estudo e análise do coeficiente de absorção acústico do compósito da fibra de cana

Pós-graduação em Engenharia Mecânica - FEIS

Avaliação da absorção colostral em neonatos ovinos da raça Bergamácia

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

Correlação entre condição da superfície do solo agrícola e o coeficiente de absorção acústica

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

Crescimento inicial e absorção de zinco pelo milho em função do modo de aplicação e fontes do nutriente

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

Interação fungo micorrízico arbuscular e adubação fosfática no crescimento e absorção de nutrientes pelo porta-enxerto limoeiro Cravo

Estudou-se o efeito da inoculação com fungo micorrízico arbuscular (FMA), Glomus etunicatum, Glomus clarum, ou Scutelospora heterogama, e da adição de fósforo solúvel (15, 30, 45, 60, 120 e 240 mg de P kg-1 de terra) sobre as variáveis altura, número de folhas, diâmetro do caule, massas vegetais aérea e radicular, teores de nutrientes nas folhas e colonização micorrízica no porta-enxerto limoeiro Cravo (Citrus limonia (L.) Osbeck). Os FMAs, Glomus etunicatum e Glomus clarum, e doses crescentes de fósforo exerceram efeitos significativos sobre essas variáveis. O efeito da inoculação sobre as variáveis de crescimento vegetal foi mais acentuado nos tratamentos com adição de 30 a 60 mg de P kg-1 de terra. Para o teor de P foliar, o efeito da inoculação foi mais acentuado nos tratamentos adicionados de 120 a 240 mg de P kg-1 de terra. A inoculação com estes FMAs aumentou a eficiência do limoeiro Cravo em absorver nutrientes, tanto que as variáveis estudadas em plantas inoculadas na ausência de adubação fosfática superaram às de plantas não inoculadas em substrato adicionado de 240 mg de P kg-1 de terra.

Absorção e níveis críticos de fósforo na parte aérea da mamoneira cultivada em diferentes classes de solos

Soil that has a high degree of weathering, with more inorganic P bound to Fe and Al oxides, has less P availability to plants. Thus, the critical element of a plant refers to the level below which the growth rate and plant production decreases, demonstrating the need for supplementary fertilization. Accordingly, an experiment was conducted in a greenhouse at Embrapa Algodao with the objective of evaluating the response of castor plants to five doses of P in four types of soil with different adsorption characteristics and critical levels of foliar P. The experimental design was completely randomized in a 4 x 5 factorial design, four types of soil and 5 levels of P with four replications. For TCo, there was an increase in height growth, with dose of 229.6 mg dm(-3) responsible for maximum plant height (74.3 cm). The largest diameter stem (17.58 mm) was observed in CXve with an application of 229.6 mg dm(-3) of P; a decrease was seen when using higher doses. The increase in leaf area was smaller in RY (4724.8 cm(2)), where it was obtained with a dose of 280.2 mg dm(-3). In general, critical levels of P in the plant shoots did not vary much between the soils. The critical level of P in castor bean shoot dry mass was higher (4.61 g kg(-1)) in TCo, this result being directly related to the low clay content of the soil.

Modelagem e simulação numérica de um sistema de refrigeração por absorção utilizando o par H2O-LiBr

The term refrigeration solar refers to any air conditioning system that uses solar energy as a primary energy source. The use of solar radiation for cooling purposes is divided according to their technological possibilities which are distinguished from one another as the way that energy is involved in the cycle, work or heat. The first case is related to vapor compression cycles, in which the work input is provided by the photovoltaic conversion of solar energy into electrical energy. In the second case, an absorption refrigeration cycle is used and the thermal energy collected from the solar radiation is provided at the generator of this cycle.. In this work a system with an absorption cycle using the pair BrLi-water, using solar energy as input is modeled. It is considered a simple refrigeration cycle whose the equations of mass and energy conservation in each component are developed in order to obtain an algebraic equation set and a simulation routine using the EES software. Although the simulation operates under certain specified thermal load it is possible to estimate the necessary areas of heat exchangers and solar collectors

Modelagem e avaliação de um sistema de refrigeração por absorção para residências e instalações de pequeno porte

This work presents a study of the absorption refrigeration system and the modeling and evaluation of two cycles using the binary solutions water-lithium bromide and ammonia-water for an equipment to be used in small size plants like residences. The study and evaluation aims the complete understanding of all parts of the system and the influence of each one of them as well as the spread of the knowledge to raise the use of this type of equipment in all sizes in order to decrease the energetic consumption of plants of all scales and making viable the alternative sources. The study is done in each element of the cycle separately and in some auxiliary equipments required in the operation such as the main power source, the solar collector. The software used for modeling, with emphasis on thermal part, was the EES (Engineering Equation Solver), that permitted the thermal balance calculus and acquisition of the used fluids properties. The results obtained for the equipment shows the system is more complex than the widely used in business, however, it can be viable and represents an alternative to increase the energetic efficiency

Avaliação do efeito tóxico do herbicida trifluralina por meio do estudo histológico e histoquímico do intestino médio do diplópodo Rhinocricus padbergi

Currently the use of pesticides in agriculture is widespread due to their high effectiveness in combating pests, weeds and diseases leading to better productivity and economical performance in agricultural area. The use of pesticides affects the whole world and their use is often performed in an improper and indiscriminate way and for long periods. Several studies have been carried out in order to verify the presence of pesticides in nature, with worrying results. The presence of higher levels of pesticides and their degradation products in soil and surface and groundwater have indicated increasing contamination. Among the most widely used pesticides, herbicides are present and among these trifluralin has occupied an important place due to its widespread use; it is an herbicide originated from benzene derivatives belonging to dinitroanilines family; it is classified as belonging to group C, being possibly carcinogenic for humans, present a high persistence in soil as a result of its low mobility and therefore may affect local edaphic fauna. Diplopods belong to a group of invertebrates considered important in the soil dynamics; due to their close contact with it, these animals can be used as bioindicators of substrates toxicity. This study aimed to expose diplopod specimens of the species R. padbergi to different concentrations of trifluralin and therefore it was mounted five bioassays containing soil from the site where animals were collected (control group) and the same soil mixed to different concentrations of trifluralin herbicide (concentration recommended for agriculture use, that is, the dose recommended by the producer 0.0534g/m2, double, haft and quarter of this dose), animals were exposed for 7 and 90 days. During the entire period of exposure (90 days), it was observed that the number of animals in the control bioassay remained stable until the 5th week, presenting only... (Complete abstract click electronic access below)