Influência das variáveis térmicas sobre os espaçamentos dendríticos terciários durante a solidificação direcional horizontal da liga Al-6%Cu

A liga Al-6%Cu foi solidificada direcionalmente sob condições transitórias de extração de calor e microestruturas dendríticas, variáveis térmicas de solidificação, ou seja, velocidade de deslocamento da isoterma líquidus (V_L), taxa de resfriamento (T_R) e gradiente de temperatura à frente da isoterma liquidus (G_L) foram caracterizadas, determinadas experimentalmente e correlacionadas com os espaçamentos dentríticos terciários (λ₃). Para tanto, foi projetado, construído e aferido um dispositivo de solidificação direcional horizontal. Os resultados encontrados mostram que leis de potência -1,1 e -0,55 caracterizam a variação dos espaçamentos terciários com a velocidade de deslocamento da isoterma liquidus (V_L) e a taxa de resfriamento (T_R), respectivamente. Finalmente, é realizado um estudo comparativo entre os resultados obtidos neste trabalho e aqueles publicados na literatura para ligas Al-Cu solidificadas direcionalmente sob condições transientes de fluxo de calor nos sistemas verticais ascendente e descendente.

Espaçamentos dendríticos primários da liga Sn-5%Pb solidificada direcionalmente em um sistema horizontal

Este trabalho desenvolve um estudo teórico-experimental sobre a correlação entre parâmetros térmicos e os espaçamentos dendríticos primários da liga Sn-5%Pb solidificada direcionalmente em um sistema horizontal sob condições transientes de extração de calor. Os perfis de temperatura foram medidos em diferentes posições do lingote e os dados obtidos foram armazenados automaticamente. São apresentados resultados para o coeficiente de transferência de calor na interface metal/molde o qual foi calculado a partir de uma análise comparativa entre os perfis térmicos experimentais e valores teóricos fornecidos por um modelo numérico. Um método teórico-experimental é aplicado para determinar as velocidades de deslocamento da isoterma liquidus e as taxas de resfriamento. Os resultados teóricos e experimentais levantados apresentaram boa concordância. Um estudo comparativo é realizado entre os dados encontrados neste trabalho e aqueles apresentados na literatura para os espaçamentos dendríticos primários da liga investigada quando solidificada direcionalmente nos sistemas verticais ascendente e descendente, sob as mesmas condições assumidas neste trabalho. A análise das microestruturas indica que os espaçamentos dendríticos primários são bastante influenciados pelos parâmetros térmicos de solidificação.

Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification

The main purpose of this paper is to investigate both the columnar to equiaxed transition and primary dendritic arm spacings of Al-3wt.%Si alloy during the horizontal directional solidification. The transient heat transfer coefficient at the metal-mold interface is calculated based on comparisons between the experimental thermal profiles in castings and the simulations provided by a finite difference heat flow program. Simulated curve of the interfacial heat transfer coefficient was used in another numerical solidification model to determine theoretical values of tip growth rates, cooling rates and thermal gradients that are associated with both columnar to equiaxed transition and primary dendritic arm spacings. A good agreement was observed between the experimental values of these thermal variables and those numerically simulated for the alloy examined. A comparative analysis is carried out between the experimental data of this work and theoretical models from the literature that have been proposed to predict the primary dendritic spacings. In this context, this study may contribute to the understanding of how to manage solidification operational parameters aiming at designing the microstructure of Al-Si alloys.

Arranjo de plantas, características agronômicas e produtividade de soja

Pós-graduação em Agronomia (Agricultura) - FCA

Produção de chicória da amazônia cultivada sob densidades de cultivo e poda do pendão floral

Chicory is a vegetable Amazon unconventional flavor that has attracted the attention of researchers for its great versatility, which makes it a promising vegetable. However, jobs are scarce in the literature on cultivation techniques for the species. This study aimed to evaluate the effect of pruning tassel floral and different spacing, the yield on Amazon chicory. Three different spacings: E1 = 0.15 x 0.15 m, with 44 plants m(2), E2 = 0.20 x 0.20 m, with 25 plants m(2), and E3 = 0.25 x 0.25 m, with 16 plants m(2), with and without pruning floral tassel. The experiment was conducted in a randomized block design in a split plot design 3 x 2, with six replications. The characteristics evaluated were: number of leaves, fresh weight and dry weight of shoots, number of tassel floral tassel floral fresh weight, yield (kg m(-2)), and leaf area index (LAI). The largest production of chicory Amazon was obtained in plants grown at a spacing of 0.25 x 0.25 m subjected to pruning floral tassel. The highest yield for Amazon chicory was obtained in plants grown at a spacing of 0.15 x 0.15 m submitted pruning floral tassel.

Massa de forragem, composição química do capim-massai e comportamento ingestivo de ovinos durante a fase de implantação do eucalipto em sistema silvipastoril

Pós-graduação em Zootecnia - FCAV

PEBD difusor nas características produtivas e fisiológicas de pimenteiro enxertado em função da densidade de plantas

Pós-graduação em Agronomia (Horticultura) - FCA

Caracterização hidráulica do aspersor Super 10 e sua influência na energia cinética e erosividade

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Facial type measurements influence on transverse dimensions of normal occlusion arches

Objective – To correlate facial type measurements of Caucasian individuals with transverse dimensions of normal occlusion arches. Methods – Twenty-one pairs of dental models were selected according to the following inclusion criteria: presence of all permanent teeth from 1 st molar to 1 st molar; normal occlusion; no prosthetic crowns; no previous orthodontic treatment and 2 mm or less of crow- dings or spacings. The cephalometric measurements of lateral cephalometric X-ray of the same individuals were taken and tabulat ed. To evaluate the repetition of arch measurements, paired Student’s t-test and Pearson's correlation coefficient were used. The r elationship between the measurements was analysed by using the Pearson’s correlation. Results – The repetition of the measurements showed high correlation and no systematic error. In the comparison between the measurements, a moderate negative correlation was observed b et- ween facial axis angle and the measurements Upper and Lower 6-6, whereas a positive correlation was observed between dentition height and the latter. Conclusion – It was observed a negative correlation between facial axis angle and upper and lower inter-molar distance as well as a positive correlation between dentition height and upper and lower inter-molar distance.

Cotton yield and fiber quality affected by row spacing and shading at different growth stages

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência dos espaçamentos de plantio da cultura de cana-de-açúcar (Saccharum spp) nos atributos físico-hídricos do solo

The evolution of sugar cane mechanized harvesting made the sector to question the current row spacing used due to its influence on soil compaction. The aim of this study was to evaluate the soil hydro-physical attributes in two row spacings after the farm machinery traffic. The treatments were conducted in a randomized block design with twelve repetitions, being subjected to the variance analyze in double factorial arrangement. The bulk density, the gravimetric water content, and the soil cone index along the position of crop lines (LC) and 0,1m from the row (LP) at the range of depth of 0 to 0.2m and 0.2 to 0.4m were assessed in both row spacings after the fourth harvest season. The results showed that the row spacings of 1.4 and 1.5m did not affect the values of bulk density and gravimetric water content of the soil in all ranges of depth and sample positions studied. However, in the depth range of 0.2 to 0.4 m, the values of soil cone index (IC) in the row spacing of 1.5 m were higher than the values in row spacing of 1.4 m, at both sampling positions. Regardless of row spacing and sample position, the values of soil cone index in the depth range of 0.2 to 0.4m were higher than the depth range of 0 to 0.2m.

Metano entérico e consumo de ovinos em sistema silvipastoril com diferentes espaçamentos arbóreos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Profundidades de semeadura e espaçamentos entre plantas na cultura do milho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Manejo de minimelancia cultivada em fibra da casca de coco, sob ambiente protegido

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

Considerações sobre a armadura transversal de pilares de concreto armado

There are regulations that establish conditions and enable the design of armor columns. The NBR 6118 features statements relating to the transverse reinforcement as spacing, reinforcement diameters provision in structural elements and others. However, the norm in force does not provide an explicit methodology for the design of stirrups in different situations. We do not propose even a calculation model for this equipment and provides normative considerations for maximum or minimum values of spacings and armor in diameter. It is noteworthy that the classical references also do not provide a calculation routine sizing of transverse reinforcement and only makes the checks as the normative conditions for the given data. Based on this assumption and the problems that may occur in sizing error, both for spacing and for the proposal of the stirrup diameter, this study demonstrates that armor calculation method already established in the literature and then through an intuitive tool and available develops a spreadsheet based on this calculation routine. It takes as reference the one developed by Emil Moersch (1902) and the calculation model proposed by BUFFONI E SILVA (2006). Finally the paper presents a rational design of shear reinforcement and confronts these values with some numerical examples to show its truth