Seeder-fertilizer machine: energetic demand as a function of vegetal covering handling and manure deposition shank depth in no-tillage system

O trabalho teve por objetivo avaliar a demanda energética de uma semeadora-adubadora, em função do tipo e manejo da cultura de cobertura vegetal e da profundidade da haste de deposição de adubo. Foi utilizado um trator Valtra BM100, instrumentado, para tracionar uma semeadora-adubadora de precisão equipada com quatro fileiras de semeadura espaçadas de 0,9 m para cultura de milho. O experimento foi conduzido em parcelas subsubdivididas, na área experimental do Laboratório de Máquinas e Mecanização Agrícola (LAMMA) da UNESP-Jaboticabal, utilizando duas culturas de cobertura (mucuna-preta e crotalária), três manejos dessas coberturas, sendo dois mecânicos (triturador de palhas e rolo-faca) e um químico (pulverização com herbicida), realizados 120 dias após a semeadura das culturas de cobertura e três profundidades da haste de deposição do adubo (0,11; 0,14 e 0,17 m), perfazendo 18 tratamentos, com quatro repetições, totalizando 72 observações. Foram avaliados os parâmetros velocidade de deslocamento, patinagem, força na barra de tração, força de pico, potência na barra de tração, potência de pico e consumo de combustível. Pôde-se concluir que a força na barra de tração foi menor para as profundidades de 0,11 e 0,14 m da haste sulcadora de adubo, o mesmo ocorrendo para força de pico, potência na barra de tração e consumo volumétrico. O consumo específico foi menor na profundidade de 0,17 m da haste sulcadora de adubo. As culturas de cobertura e seus manejos não interferiram no desempenho das máquinas estudadas.

Droplet deposition during spray and leaf pH in aquatic weed control

A diversidade morfológica da superfície foliar existente entre as espécies de plantas e a presença de estruturas foliares como tricomas, estômatos, cutícula e ceras podem exercer grande influência na aderência e deposição das gotas de pulverização, assim como na absorção do herbicida. Desta forma, o objetivo do presente trabalho foi estudar, em quatro espécies de plantas daninhas aquáticas (Enhydra anagallis, Eichhornia crassipes, Heteranthera reniformis e Typha subulata), a área de molhamento de gotas de pulverização nas superfícies foliares adaxial e abaxial, bem como o pH foliar. O experimento foi realizado em Botucatu-SP. As plantas foram cultivadas em caixas d'água sob condições de campo, e quando atingiram seu pleno desenvolvimento (antes do florescimento), foram realizadas as avaliações de pH foliar e da área de molhamento de gotas de pulverização. As tensões superficiais das gotas aplicadas (0,5 mL), apresentadas pelas soluções de glyphosate aplicado isolado a 5,0% v v-1 (Rodeo 480 g L-1 e.a. produto comercial), glyphosate + Aterbane BR (5,0% + 0,5% v v-1), glyphosate + Silwet L-77 (5,0% + 0,05% v v-1), além das soluções com os adjuvantes isolados, Aterbane BR (0,5% v v-1) e Silwet L-77 (0,05% v v-1) foram respectivamente 72,1; 28,7; 23,3; 37,3 e 22,1 mN m-1. As médias obtidas de pH foliar variaram entre 5,50 e 7,50, destacando-se a espécie E. anagallis com valores de 6,68 e 7,02 para as faces adaxial e abaxial, respectivamente. Dentre as plantas daninhas aquáticas avaliadas T. subulata foi a espécie que apresentou as maiores médias de área de molhamento nas faces adaxial e abaxial da folha, proporcionada pelas as soluções de glyphosate + Aterbane BR, glyphosate + Silwet L-77 e Silwet L-77, com valores de 12,99-7,03; 20,04-17,95 e 31,81-25,91 mm², respectivamente.

Spray deposition and losses in potato as a function of air-assistance and sprayer boom angle

A cultura da batata possui grande expressão econômica dentro do cenário agrícola. Para isso, equipamentos e técnicas de aplicação de produtos fitossanitários vêm sendo desenvolvidos visando melhorar o rendimento econômico da cultura. Neste sentido, experimentos foram conduzidos no delineamento em blocos ao acaso na cultura da batata cv. Ágata. Objetivando avaliar o efeito da assistência de ar combinada a diferentes ângulos de aplicação sobre a deposição da pulverização, bem como as perdas da calda para o solo utilizou-se um pulverizador com e sem assistência de ar junto à barra de pulverização posicionada a +30º, 0º e -30º (sinal + a favor e - contrário ao deslocamento) em relação a vertical. O volume de calda foi 400 L ha-1 utilizando-se pontas de jato cônico vazio JA-4 na pressão de 633 kPa. Para a avaliação dos depósitos utilizou-se um traçador cúprico. Os depósitos foram removidos dos folíolos por lavagem com água destilada, em ambas as superfícies foliares, nas posições superior e inferior das plantas de batata e quantificados por espectrofotometria de absorção atômica. As perdas da pulverização foram avaliadas em coletores plásticos colocados nas entrelinhas das parcelas experimentais. Os níveis dos depósitos do traçador cúprico nas diferentes posições da planta foram analisados pelo teste estatístico T² de Hotteling. Os maiores depósitos foram obtidos com a barra posicionada a 0º e +30º, em presença da assistência de ar, tanto na posição superior quanto inferior da planta. A presença do ar, além de propiciar maiores depósitos na parte inferior das plantas, possibilitou maior uniformidade na distribuição deles. As perdas da pulverização ficaram abaixo de 4%.

Sojas integrais tostada pelo vapor e extrusada em rações de poedeiras

An experiment with 400 laying hens Hy Line with 26 weeks of age was conducted to compare the performance of laying hens fed during four cycles of 28 days with diets containing soybean meal (SM) plus soybean oil (SBM+oil), whole extruded soybean (ESB) and whole steam toasted soybean (TSB). A completely design randomized blocks was used, with 10 treatments and five replicates and eight laying hens in each experimental unit. The treatments consisted on the replacement of SBM per ESB and TSB at the levels 0, 25, 50, 75 and 100%; and as control the SBM with or without addition of oil. The results obtained showed that the hens were able to regulate the feed intake to maintain the energy intake only at lower energetic levels, however they tended to over intake energy with the increase of energy levels of the diets. The addition of oil or soybeans in the diets improved feed: gain ratio, however worsened the energy efficiency in relation to the diet without oil. The processing of soybean provided differences on the performance of laying hens and the ESB showed to be superior to TSB. The hens had higher use of the oil added to the soybean meal (SBM + oil) and ESB in relation to TSB. However, the values of AMEn obtained for the ESB were 12% higher, in average, to those determined for the SBM + oil and for the TSB.

Photoluminescence at room temperature in amorphous SrTiO3 thin films obtained by chemical solution deposition

Intense photoluminescence in highly disordered strontium titanate amorphous thin films prepared by the polymeric precursor method was observed at room temperature (300 K). The luminescence spectra of SrTiO3 amorphous thin films at room temperature revealed an intense single-emission band in the visible region. X-ray absorption near edge structure was used to probe the local atomic structure of SrTiO3 amorphous and crystalline thin films. Photoluminescence intensity in the 535 nm range was found to be correlated with the presence of non-bridging oxygen defects. A discussion is presented of the nature of this photoluminescence, which may be related to the disordered structure in SrTiO3 amorphous thin films. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Soft chemical deposition of BiFeO3 multiferroic thin films

BiFeO3 thin films free of secondary phases were obtained by the soft chemical solution on Pt(111)/Ti/SiO2/Si substrates after annealing at 500 degrees C for 2 h. The film grown in the (100) direction presented a remanent polarization P-r of 31 mu C/cm(2) at room temperature. Electrical measurements using both quasistatic hysteresis and pulsed polarization confirm the existence of ferroelectricity with a switched polarization of 60-70 mu C/cm(2), Delta P=(P-*-P). Low leakage conduction and an out-of-plane piezoelectric (d(3)) coefficient of 40 pm/V were obtained by the improvement of preparation technology.

Ultrastructure of early mineral deposition during hyaline layer formation in rat molars

There is no consensus on whether the first mineralized layer, the hyaline layer, that is juxtaposed to root dentine is a variety of dentine or cementum or even a tissue of epithelial origin. Some suggest that there is no intermediate tissue between the acellular extrinsic fibre cementum (AEFC) and the root dentine. Here, to study hyaline layer formation and mineralization we examined by transmission electron microscopy the early stages of root development in upper molars from 10 to 13 day old Wistar rats. In addition to conventionally processed material, undemineralized and unstained sections were examined, which showed the deposition of fine mineral crystals in contact with the mineralized surface of root dentine. Early mineralization of the hyaline layer occurred in the region of the inner basement membrane, which persisted between the inner cellular layer of Hertwig's epithelial root sheath and the outer mineralized root dentine. When the root sheath began its fragment, collagen fibrils From the developing periodontal ligament began to insert into the mineralising hyaline layer, which was 0.5-0.8 mum wide. As the fragmentation of the root sheath HERS increased, more collagen fibrils appeared intermingled with the mineralising hyaline layer. In more advanced stages, when the hyaline layer had become fully mineralized and the formation of the AEFC began, the hyaline layer could no longer be identified. Thus, the hyaline layer is clearly discernible at early stages of periodontal development. Subsequently, it is masked by intermingling of cementum and dentine and therefore it is not possible to detect it in the formed roots of rat molars. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Influence of agricultural biomass burning on aerosol size distribution and dry deposition in southeastern Brazil

The size distributed composition of ambient aerosols is used to explore seasonal differences in particle chemistry and to show that dry deposition fluxes of soluble species, including important plant nutrients, increase during periods of biomass (sugar cane trash) burning in São Paulo State, Brazil. Measurements were made at a single site centrally located in the State's sugar cane growing region but away from the immediate vicinity of burns, so that the air sampled was representative of the regional background. Calculation of ion equivalent balances showed that during burning periods smaller particles (Aitken and accumulation modes) were more acidic, containing higher concentrations of SO(4)(2-), oxalate, NO(3)(-), HCOO(-), CH(3)COO(-), and Cl(-), but insufficient NH(4)(+) and K(+) to achieve neutrality. Larger particles showed an anion deficit due to the presence of unmeasured ions and comprised resuspended dusts modified by accumulation of nitrate, chloride, and organic anions. Increases of resuspended particles during the burning season were attributed to release of earlier deposits from the surfaces of burning vegetation as well as increased vehicle movement on unsurfaced roads. During winter months the relative contribution of combined emissions from road transport and industry diminished due to increased emissions from biomass combustion and other activities specifically associated with the harvest period. Positive increments in annual particulate dry deposition fluxes due to higher fluxes during the sugar cane harvest were 44.3% (NH(4)(+)), 42.1 % (K(+)), 31.8% (Mg(2+)), 30.4% (HCOO(-)), 12.8% (Cl(-)), 6.6% (CH(3)COO(-)), 5.2% (Ca(2+)), 3.8% (SO(4)(2-)), and 2.3% (NO(3)(-)). Na(+) and oxalate fluxes were seasonally invariant. Annual aerosol dry deposition fluxes (kg ha(-1)) were 0.5 (Na(+)), 0.25 (NH(4)(+)), 0.39 (K(+)), 0.51 (Mg(2+)), 3.19 (Ca(2+)), 1.34 (Cl(-)), 4.47 (NO(3)(-)), 3.59 (SO(4)(2-)), 0.58 (oxalate), 0.71 (HCOO(-)), and 1.38 (CH(3)COO(-)). Contributions of this mechanism to combined aerosol dry deposition and precipitation scavenging (inorganic species, excluding gaseous dry deposition) were 31% (Na(+)), 8% (NH(4)(+)), 26% (K(+)), 63% (Mg(2+)), 66% (Ca(2+)), 32% (Cl(-)), 33% (NO(3)(-)), and 36% (SO(4)(2-)).

Microstructural and transport properties of LaNiO3-delta films grown on Si(111) by chemical solution deposition

Electrically conductive LaNiO3-delta (LNO) thin films with typical thickness of 200 nm were deposited on Si (111) substrates by a chemical solution deposition method and heat-treated in air at 700 degreesC. Structural, morphological, and electrical properties of the LNO thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), field-emission scanning electron microscopy (FEG-SEM), and electrical resistivity rho(T). The thin films have a very flat surface and no droplet was found on their surfaces. The average grain size observed by AFM and FEG-SEM was approximately 100 nm in excellent agreement with XRD data. The rho(T) data showed that these thin films display a good metallic character in a large range of temperature. These results suggest the use of this conductive layer as electrode in the integration of microelectronic devices. (C) 2003 Elsevier B.V. All rights reserved.

SrBi2Ta2O9 ferroelectric thick films prepared by electrophoretic deposition using aqueous suspension

SrBi2Ta2O9 ferroelectric thick films were prepared by electrophoretic deposition (EPD). For that, ceramic powders were prepared by chemical method in order to obtain compounds with chemical homogeneity. The polymeric precursor method was used for the synthesis of the SrBi2Ta2O9 powder. The crystallographic structure of the powder was examined by X-ray diffraction, and the surface area was determined by single point BET adsorption. The 0.03 vol.% suspension was formed by dispersing the powder in water using two different polymers as dispersants: an ester polyphosphate (C213) and an ammonium polyacrilate (Darvan 821-A). It was investigated the influence of the different dispersants in the surface properties of the powder by zeta potential measurements. The films were deposited on platinum-coated alumina and Pt/Ti/SiO2/Si substrates by a 4 mA constant current, for 10 min, using two parallel electrodes placed at a separation distance of 3 min in the suspension. Several cycles of deposition-drying of the deposit were carried out until reaching the desired thickness. After thermal treatment at temperatures ranging from 700 to 1000 degreesC, the films were characterized by X-ray diffraction and scanning electron microscopy for the microstructure observation. (C) 2003 Elsevier Ltd. All rights reserved.

Electrical characterization of SnO2 : Sb ultrathin films obtained by controlled thickness deposition

A representative study is reported on the electrical properties of SnO2: Sb. ultrathin films (thickness of 40-70 nm) produced by a deposition method based on aqueous colloidal suspensions of 3-5 nm crystalline oxides. The results revealed the films' electrical behavior in a range of 10-300 K, showing a strong dependence on dopant incorporation, with minimum resistivity values in 10 mol % of Sb content. All the samples displayed semiconductor behavior, but the transport mechanism showed a strong dependence on thickness, making it difficult to fit it to well-known models. In thicker films, the mechanism proved to be an intermediary system, with thermally activated and hopping features. Electron hopping was estimated in the range of 0.4-1.9 nm, i.e., in the same order as the particle size. (c) 2007 American Institute of Physics.