Prazeres C.S.,Santa Catarina State University |
Semina:Ciencias Agrarias | Year: 2017
The hydration pattern associated with the physiological quality of seeds can be an early indicator for the evaluation of seed quality. The present study aimed to evaluate the hydration pattern of seeds subjected, or not, to water restriction, and to relate these patterns to their physiological quality. The physiological quality of seeds from five maize lines (L1, L2, L3, L4, and L5) and four hybrids (HT1, HT2, HS1, and HS2) was initially determined using seed germination and vigor tests (accelerated ageing and electric conductivity). A completely randomized experimental design was used with four repeats for the physiological analyses and a regression analysis was performed in order to assess the behavior of the seeds over time. The hydration curve was determined by imbibing the seeds in distilled water 0,0 MPa (control) and in a -0.9 MPa osmotic solution of polyethylene glycol 6000. Water uptake by the seeds was found to follow a triphasic pattern in the absence of water stress (0.0 MPa), however, when exposed to a -0.9 MPa osmotic potential, an extended phase II was observed. Diversity was observed between the lines in terms of the hydration pattern of the seeds, which can influence the physiological quality of the hybrid seeds. Regarding the hybrids, a positive relationship was observed between the shortest time to root protrusion and the quality of the seeds, both with or without water restriction, which allows us to conclude that hydration pattern can be used as a parameter for the early evaluation of physiological quality in hybrid maize seeds.
Ruthes J.R.,WEG Equipamentos Eletricos S.A. |
Nau S.L.,WEG Equipamentos Eletricos S.A. |
2016 12th IEEE International Conference on Industry Applications, INDUSCON 2016 | Year: 2017
Three-phase induction motors fed by frequency inverters have become an increasingly used solution for applications that require torque and speed control. The harmonic content of inverter output voltage generates harmonics in the motor current. Both harmonics produce harmful effects on motor performance. To estimate accurately these effects in the design stage of electric motors is not a simple task. Not all the phenomena that occur in electrical machines are fully modeled, especially when considering the harmonic voltage of non-sinusoidal supply. The numerical methods that currently have satisfactory results penalize the project with expensive computational cost and time. Analytical models are very common and useful for analyzing small changes in current projects, but they have limitations to deal with new project evaluation. To determine the influence of voltage harmonics three approaches were tested and compared with experimental results. © 2016 IEEE.
Bressan J.D.,UDESC |
Moreira L.P.,UFF |
AIP Conference Proceedings | Year: 2016
Present work examines mathematical models to predict the onset of localized necking in sheet metal forming of interstitial free steel, such as biaxial stretching and deep drawing. Forming Limit Curve, FLC, which is an essential material parameter necessary to numerical simulation by FEM, of IF steel sheet was assessed experimentally by Nakajima testing and ASAME software. The "Map of Principal Surface Limit Strains - MPLS", shows the experimental FLC which is the plot of principal true strains in the sheet metal surface (ϵ1, ϵ2), occurring at critical points obtained in laboratory formability tests or in the fabrication process of parts. Two types of undesirable rupture mechanisms can occur in sheet metal forming products: localized necking and rupture by induced shear stress. Therefore, two kinds of limit strain curves can be plotted in the forming map: the local necking limit curve FLC-N and the shear stress rupture limit curve FLC-S. Localized necking is theoretically anticipated to occur by two mathematical models: Marciniak-Kuczynski modeling, hereafter named M-K approach, and D-Bressan modeling. In the M-K approach, local necking originates at an initial sheet thickness heterogeneity or defect fo = tob/toa. The strain state inside the evolving groove moves to plane strain and the limit strain ϵ1 ∗ is attained when the strain ϵ1a outside the groove or neck stop to increase. In the D-Bressan model, local necking is proposed to initiate at the instability point of maximum load, at a thickness defect (λ/μ)diffuse inside the grooved sheet thickness. The inception of visible grooving on the sheet surface evolves from instability point to localized (λ/μ)crit and final rupture, during further sheet metal straining. Work hardening law is defined for a strain and strain-rate material by the effective current stress. The average experimental hardening law curve for tensile tests at 0°, 45° and 90°, assuming normal anisotropy, was used to analyze the plasticity behavior during the biaxial stretching of sheet metals. Theoretical predicted curves of local necking limits are plotted in the positive and negative region of MPLS for different defect values fo and λ/μ parameters. Limit strains are obtained from a software developed by the authors. Experimental results of FLC obtained from experiments for IF steel sheets were compared with the theoretical predicted curves: the correlation is reasonable good in the positive quadrant, but the predicted values are above the experimental points in the negative quadrant due to punch friction, non-linear strain path and grid measurements. © 2016 Author(s).
Bertol I.,Santa Catarina State University |
Bertol C.,Representacoes Comerciais e Projetos Industriais Ltda |
Revista Brasileira de Ciencia do Solo | Year: 2012
The use of rain simulators is fundamental to study rainfall erosion. They are used to monitor the experimental conditions, particularly the rain characteristics and to understand the soil erosion process better. Several types of rainfall simulators have been developed since 1930 around the world. Currently, the Swanson model is the most commonly used. However, a small number of these simulators is fully operational in Brazil, due to the high degree of wear and difficulties of maintenance. The purpose of this study was to develop a new rainfall simulator model, made mostly of aluminum, with no motor to rotate the booms and driven by hydraulic thrust. This "water thrust" rainfall simulator maintains the general features of the Swanson model, mainly those related to the characteristics of the rainfall produced, but with less weight, making the gasoline engine to move the booms superfluous. These properties make this new model lighter, economical, quiet and easier to move about in the experimental area than the model Swanson, since it can be dislocated by only four persons. The rainfall intensity was linearly and positively correlated with the water pressure of the manometer.
Barbieri R.,UDESC |
Machado R.D.,Federal University of Paraná
Latin American Journal of Solids and Structures | Year: 2015
The Modified Global Green's Function Method (MGGFM) is an integral technique that is characterized by good accuracy in the evaluation of boundary fluxes. This method uses only projections of the Green's Function for the solution of the discrete problem and this is the origin of the term 'Modified' of its name. In this paper the local strategy for calculating the projections of Green's function using de Finite Element Method (FEM) are detailed. The numerical examples show some aspects of the method that had not yet been observed and good results for the flux in all nodes of the mesh. © 2015, Brazilian Association of Computational Mechanics.All right reserved.
Tasca F.A.,Santa Catarina State University |
Ernani P.R.,Brazilian National Council for Scientific and Technological Development |
Rogeri D.A.,UDESC |
Gatiboni L.C.,Brazilian National Council for Scientific and Technological Development |
Cassol P.C.,Brazilian National Council for Scientific and Technological Development
Revista Brasileira de Ciencia do Solo | Year: 2011
Ammonia volatilization is an important process of N loss which decreases the use efficiency of N by plants when urea is applied on the soil surface. To overcome this problem, some chemical compounds were mixed with urea to inhibit the urease action. The purpose of this study was to compare applications of an alternative fertilizer with urease inhibitor to reduce ammonia volatilization with conventional urea, under certain environmental and soil conditions. Four experiments were carried out in 2007 and 2008, under laboratory conditions, with samples of a Humic Haplumbrept. The treatments varied according to each experiment in terms of soil conditions, such as pH (4.0, 5.5, 6.3 and 6.8), soil water content (5, 10 or 20 % moisture), temperature (18 or 35°C), aside from the fertilizer physical state (solid or liquid) and application method (over the surface or soil-incorporated). The experimental units consisted of plastic trays into which 12 kg of soil (dry basis) were filled in a 15 cm layer. Ammonia gas traps were installed across the soil surface. Frequent measurements were performed during the first 28 days of soil-fertilizer incubation. The peak of ammonia volatilization from the soil occurred in the first week after the application of traditional urea, and two or three days later for urea with urease inhibitor. Ammonia loss was not always higher from conventional than from treated urea, nor from solid than from liquid fertilizers. Ammonia volatilization increased with increases in soil pH, temperature and N rate and was lower at the lowest (5 %) and highest (20 %) soil moisture content. For surface-applied fertilizers, the maximum daily N loss rate was 14 kg ha-1 and the total cumulative loss ranged from 2 to 50 % of the applied N, depending mainly on the physical state of the fertilizer, temperature and on soil moisture. Soil incorporation of urea fertilizers was the best option to minimize ammonia volatilization in all treatments.
Ehrhardt-Brocardo N.C.M.,Santa Catarina State University |
Semina:Ciencias Agrarias | Year: 2016
This study aimed to investigate the relationship between the hydration pattern of landrace bean genotypes and their physiological quality. The hydration curve of eight landrace (BAFs 07, 13, 23, 42, 44, 50, 55, 81) and two commercial cultivars (IPR-88-Uirapurú and Iapar 81) genotypes was determined from seed moisture. Determination of initial physiological quality was performed by germination and vigor tests (seedling performance and accelerated aging). Characterization of the genotypes, regarding accelerated aging tests, showed that BAFs 13, 42, 55 and 81 had the highest physiological potential, whereas BAFs 07, 23, 44, 50 and the commercial cultivars had lower physiological quality. The hydration curve followed a triphasic pattern with radicle protrusion occurring between 21 and 27 hours after seed hydration. The percentage of reserves translocated to the seedling during formation showed that BAF 42 had the highest conversion efficiency compared to the smaller efficiencies of BAFs 23, 50 and Iapar 81. The seedling length test showed that BAFs 42 and 55 had the most vigorous seedlings, which was driven by the high percentage of reserves translocated to the seedling during formation. BAFs 23, 50 and the cultivar Iapar 81 showed lower reserve translocation, demonstrating that low mobilization potential leads to smaller seedlings. The hydration of bean seeds during germination was affected by physiological quality, as genotypes considered more vigorous exhibited higher hydration rates than those of the less vigorous genotypes.
Nava G.,Sao Joaquim Experimental Station |
Ernani P.R.,Santa Catarina State University |
de Sa A.A.,UDESC |
Pereira A.J.,Sao Joaquim Experimental Station
Revista Brasileira de Ciencia do Solo | Year: 2012
Gypsum does not affect the soil negative charges and maintains sulfate in the soil solution, making it one of the cheapest products to increase Ca activity in soil solution, especially in the deeper soil layers. Higher Ca levels in the soil solution can increase the uptake of this nutrient by apple trees, reducing the risk of physiological disorders caused by Ca deficiency. This study assessed the effect of long-term gypsum application on some soil properties and on the chemical composition of leaves and fruits of an apple cultivar susceptible to fruit disorders associated with low Ca. The experiment was conducted in São Joaquim, in the South of Brazil, from 2001 to 2009. Gypsum rates of 0, 1.0, 2.0 and 3.0 t ha-1 were annually broadcast over the soil surface, without incorporation, in an apple orchard with cultivar 'Catarina', planted in 1997. Gypsum application over eight consecutive years had no effect on soil exchangeable K and Al to a depth of 80 cm, but increased exchangeable Ca in the sampled layers (0-10, 10-20, 40-60 and 60-80 cm), while exchangeable Mg decreased only in the surface layer (0-20 cm). Gypsum did not affect the concentration of any nutrient in the fruits, including Ca. The same was verified in the leaves, except for Mg which decreased with increased gypsum rate. Despite increasing the availability of Ca in the soil profile to a depth of 80 cm, gypsum was not effective to increase the Ca content in leaves and fruits of an apple cultivar susceptible to Ca deficiency grown in an appropriately limed soil.
Soccol O.J.,UDESC |
Cardoso C.O.,UDESC |
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2010
In this study, monthly rainfall time-series with 80 years of collected data were analyzed and adjusted using gamma distribution in order to determine the expected monthly rainfall for Lages, in the State of Santa Cararina. The method of adjustment of model was used to estimate α and β parameters of gamma distribution, and Kolmogorov-Smirnov's test assessed the model's fitting to the data. Gamma distribution fitted to observed data of all months of the year (p < 0.05). From the adjusted distribution, the monthly rainfall was estimated for the probability levels of 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 75, 80, 90 and 95%, which correspond to occurrence of probable minimum precipitation P(X > x). The results showed that the monthly mean rainfall, for all months of the year, occurred at probability level of 31.93% with variation coefficient of 3.63%. Considering these results, it is proved that the found mean values should not be used as parameters in agricultural projects. For all months of the year, the difference between monthly mean rainfall and probable rainfall were 64.49 mm (51.3%) and 73.03 mm (58.1%), at probability levels of 75 and 80% respectively.
AIP Conference Proceedings | Year: 2010
Present work examines a new mathematical model to predict the onset of localized necking in the industrial processes of sheet metal forming such as biaxial stretching. Sheet metal formability is usually assessed experimentally by testing such as the Nakajima test to obtain the Forming Limit Curve, FLC, which is an essential material parameter necessary to numerical simulations by FEM. The Forming Limit Diagram or "Forming Principal Strain Map" shows the experimental FLC which is the plot of principal true strains in the sheet metal surface, ε1 and ε2, occurring at critical points obtained in laboratory formability tests or in the fabrication process. Two types of undesirable rupture mechanisms can occur in sheet metal forming products: localized necking and shear induced fracture. Therefore, two kinds of limit strain curves can be plotted: the local necking limit curve FLC-N and the shear fracture limit curve FLC-S. Localized necking is theoretically anticipated to initiate at a thickness defect fin=hib/hia inside the grooved sheet thickness hia, but only at the instability point of maximum load. The inception of grooving on the sheet surface evolves from instability point to localized necking and final rupture, during further sheet metal straining. Work hardening law is defined for a strain and strain rate material by the effective stress σ̄= σo(1+βε̄)nεM. The average experimental hardening law curve for tensile tests at 0°, 45° and 90°, assuming isotropic plasticity, was used to analyze the plasticity behavior during the biaxial stretching of sheet metals. Theoretical predicted curves of local necking limits are plotted in the positive quadrant of FPSM for different defect values in and plasticity parameters. Limit strains are obtained from a software developed by the author. Some experimental results of forming limit curve obtained from experiments for IF steel sheets are compared with the theoretical predicted curves: the correlation is good. © 2010 American Institute of Physics.