ABSTRACT Although numerous studies have been conducted with common bean regarding nitrogen (N) dose, time of application, and source in no-till (NT) soils in Brazil, the heterogeneity of the results makes it difficult to establish technical recommendations based on individualized studies. This meta-analysis aimed to rank the main factors influencing common bean response to N management in NT areas. The database consisted of 99 scientific papers that encompassed 160 trials and 2394 observations. In general, the probability of obtaining a positive response to N application in common bean productivity was 77 %, with an average 18 % increment (358 kg ha-1). The main factors that affect the response of common bean grain yield to N fertilization and the choice of the applied N dose are soil organic matter (OM) content and the preceding crop. In soils with OM content >20 g kg-1, the N dose that determines the highest economic return is 50 kg ha-1. For soils with OM content <20 g kg-1, the N dose to be applied is 70 and 100 kg ha-1 for crops preceded by legumes and grasses, respectively. The timing of the N application did not result in a significant difference in common bean yield in 62 % of the trials. However, the results showed that the average yield increase in the common bean went from 15 % (293 kg ha-1) with a single application to 32 % (622 kg ha-1) with split N applications. All N sources tested showed similar gains to those obtained with N application through urea. Excluding situations with high doses of N application (>100 kg ha-1), inoculating common bean seeds increased grain yields by 6 % on average (118 kg ha-1). The combined analysis of the available results demonstrated that the crop recommendations used in Brazilian soils under NT could be refined considering the soil OM concentration and preceding crop. Additionally, seed inoculation and N dose splitting in the form of common urea should be recommended.

AbstractThis paper shows successful hindering of the negative effects of the cobalt binder in the process of coating WC-Co cutting tools with CVD diamond films. The strategy was creating a boron-rich layer on the surface of the WC-Co substrates as an interlayer to block Co migration. The traditional boriding technique was improved by preheating the salt powders and controlling the brittle region thickness in the substrate surface. These procedures produce a tougher surface for diamond growth. Adding CF4 to the gas mixture also enhanced diamond adhesion to the surface. The adhesion of diamond films to WC-Co substrates was evaluated by indentation tests. Samples were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD) and Raman Scattering Spectroscopy (RSS).

ABSTRACT: The noise source distribution of a short-cowl coaxial jet operating at different velocity ratios is described in this work. This was motivated by an ongoing research about noise prediction of coaxial jets through Acoustic Analogy with purposes of industrial engine application. This research has been carried out between Universidade Federal de Uberlândia (UFU), Brazil and the Institute of Sound and Vibration Research (ISVR) at Southampton University, UK. The numerical approach employed is originally based on Lighthill Acoustic Analogy. This technique, although likely known, is associated with an improved energy transfer time-scale, used in the turbulence two-point correlation function, in order to enhance the source model. The source model is coupled with the aerodynamic calculation of flow through turbulence quantities evaluated by using a standard k-ε turbulence modeling. The Computational Fluid Dynamics data have also been used to provide complementary information about the coaxial jet noise production mechanisms. Experimental data were used in order to corroborate the results from the current model. Good agreement has been found, showing that high and low frequency contributors to the radiated noise for low velocity ratio are aggregated in a region about seven to ten secondary diameters downstream, while at higher velocity ratios sources are continuously spread from about one up to ten secondary diameters from the jet exit.

Realizaram-se crescimentos de filmes de diamante por deposição química de vapor (CVD, do inglês Chemical Vapor Deposition) em substratos de silício (100), de grande área (80 cm²), em um reator de filamento quente (HFCVD), com taxas de crescimento superiores a 1,5 µm/h. Foi realizado o crescimento das amostras com diferentes fluxos gasosos e diferentes porcentagens de metano (CH4) em hidrogênio (H2). As amostras foram caracterizadas por microscopia óptica, eletrônica de varredura e por espectroscopia de espalhamento Raman. Tais análises acusaram a presença de diamante de alta pureza em todas as amostras.

Diamond films were grown through Chemical Vapor Deposition (CVD) in silicon substrates (100) of large area (80 cm²), in a hot filament chemical vapor deposition (HFCVD), with growth rates over 1,5 µm/h. The growth of samples was made with different gaseous fluxes and different methane percentages (CH4) in hydrogen (H2). The samples were analyzed through optical microscopy, Scanning Electron Microscopy and Raman spectroscopy scattering. Such analyzes showed the presence of a high purity diamond in all samples.

Os objetivos deste trabalho foram determinar a herança da resistência ao complexo de enfezamento em milho e determinar as melhores fontes de resistência entre as linhagens estudadas. Foram realizadas as análises dialélica e médias de gerações em linhagens de milho. Para a análise dialélica, foram cruzadas 12 linhagens de milho, em dialélico parcial. Para análises de médias de gerações, foram cruzadas três linhagens resistentes e quatro suscetíveis, para a obtenção das gerações F1, F2, RCP R e RCP S. Os trabalhos foram conduzidos em Jaboticabal, SP. A incidência de enfezamento foi avaliada no estádio fenológico R3. Efeitos significativos quanto à capacidade geral de combinação e capacidade específica de combinação foram obtidos, o que indicou que, no controle do caráter enfezamentos, estão envolvidos tanto os efeitos aditivos quanto os de dominância. Análises de médias de gerações mostraram a presença de poucos genes envolvidos com o controle da resistência, com predominância de efeitos aditivos, o que permite a seleção de genótipos resistentes. As linhagens L02, L03 e L05 poderão ser utilizadas como fontes de resistência, em futuras combinações híbridas.

The objectives of this work were to determine the inheritance of resistance to corn stunt and determine the best resistance sources among the studied inbred lines. Diallel analysis and generation means were made for corn inbred lines. For the diallel analysis, twelve corn-inbred lines were crossed, in a partial diallel scheme. For the analyses of generation means, three resistant inbred lines and four susceptible ones were crossed, to obtain the F1, F2, RCP R and RCP S generations. The experiments were carried out in Jaboticabal, SP, Brazil. Corn sfunt incidence was evaluated at the phenological phase R3. Significant effects for CGC and CEC were obtained, which indicated that both additive and dominance effects were involved in corn expression of resistance to stunt. The analyses of generation means showed that few genes are involved in the resistance control, with predominant additive effects, which allows the selection of resistant genotypes. Lineages L02, L03 and L05 may be used as resistance sources in future hybrid combinations.

O preparo dos substratos, para o crescimento de filmes de diamante CVD, é de fundamental importância por diversos fatores. Um novo método de preparação dos substratos de molibdênio, o jateamento por óxido de alumínio, é apresentado e comparado com os métodos tradicionais de preparo. As amostras de diamante CVD obtidas foram analisadas por espectroscopia de espalhamento RAMAN e por microscopia eletrônica de varredura (MEV). Obtiveram-se filmes de diamante CVD de boa qualidade e uniformidade e o novo processo proposto de tratamento do substrato de molibdênio permitiu maior taxa de crescimento que os métodos tradicionais.

The substrate preparation for CVD diamond growth is of basic importance due to several reasons. A new molybdenum substrate preparation method, the aluminum oxide abrasion jetting, is introduced and compared with the traditional ones. Raman Scattering Spectroscopy (RSS) and Scanning Electron Microscopy (SEM) characterize CVD diamond films. CVD diamond films of good quality and uniformity were obtained. The substrate preparation by aluminum oxide blasting allowed for a higher nucleation rate.

Surfaces with very poor mechanical and frictional properties can be improved, or even, acquire new properties similar to diamond if good adherent CVD diamond film is obtained on it. In this work, nitrogen ions were sub-implanted on pure molybdenum as a means to enhance CVD diamond film adherence. Deposition time from 2 up to 60 h were used for deposition of 10 to 400 µm thick CVD diamond films with very good adherence on sub-implanted molybdenum substrate. Characterizations were carried out by XPS, X-ray diffraction and nano indentation on prepared surfaces prior to diamond growth and after the onset nucleation. The ionic sub-implantation with nitrogen possibly assists in adhesion, with the creation of a thin layer of nitrates and complexes.