De Oliveira C.R.,Federal University of São Carlos |
Journal of Physics A: Mathematical and Theoretical | Year: 2010
We consider the Hamiltonian operator associated with planar sections of infinitely long cylindrical solenoids and with a homogeneous magnetic field in their interior. First, in the Sobolev space H2, we characterize all generalized boundary conditions on the solenoid border compatible with quantum mechanics, i.e. the boundary conditions, so that the corresponding Hamiltonian operators are self-adjoint. Then we study and compare the scattering of the most usual boundary conditions, that is, Dirichlet, Neumann and Robin. © 2010 IOP Publishing Ltd.
De Melo T.J.A.,Federal University of Campina Grande |
Pinheiro L.A.,UEPG |
Canevarolo S.V.,Federal University of São Carlos
Polimeros | Year: 2010
Residence time distribution (RTD) is a very important parameter in extrusion, either for simple polymer processing or for special processes like compounding, blending, reactive compatibilization, and controlled degradation. This work deals with the values of mean residence time (tn) as a function of the number of 45 degrees kneading elements in the screw profile, screw speed, and feeding rate. The tn values were calculated from the RTD curves, which in turn were determined by the technique of a marker added as a pulse in the steady state polymer flow. The values of tn were empirically modeled as a function of those parameters. The results showed that feeding rate is the most influent parameter, followed by number of kneading elements and screw speed. The modeling has given a quadratic function relating t and the operational parameters tested.
de Oliveira C.R.,Federal University of São Carlos |
Letters in Mathematical Physics | Year: 2011
Consider bounded solenoids in the space or planar approximate models of infinitely long solenoids. It is proved that the solenoid impenetrability, by means of a sequence of Hamiltonians with diverging potentials, converges in the norm resolvent sense to the usual Aharonov-Bohm model with Dirichlet boundary condition. The framework is that of nonrelativistic quantum mechanics. © 2010 Springer.
Giarola N.F.B.,UEPG |
da Silva A.P.,University of Sao Paulo |
Tormena C.A.,State University of Maringa |
Ball B.,SAC |
Scientia Agricola | Year: 2010
Methods for evaluation the soil structure quality based on field evaluations are useful to determine strategies for soil management, with the advantage of requirement the use of little equipment and the possibility of immediate interpretation. A new methodology was recently developed to temperate soils for this purpose, called Visual Soil Structure Assessment (Ball et al., 2007). It was tested the hypothesis that it is possible to apply and advance in the interpretation of the results from use of Visual Soils Structure Assessment in cultivated Oxisols. Therefore the goal of this study was to apply, evaluate and enhance the potential of the methodology developed by Ball et al. (2007) in two Oxisols under long-term, no-till in Parana State, Brazil, as well as in a soil under native forest, used as reference of soil structural quality. The proposed implementation and progress in terms of structural quality for the distinct layers provided an assessment of soil physical quality more practical and detailed. This is useful to support the selection of appropriate techniques for mechanical and biological management systems in order to achieve the physical quality of soil suitable for crop development. Visual scores of soil structure quality proposed by Ball et al. (2007) can be applied to Brazilian Oxisols cultivated under no-tillage system.
Silva S.G.C.,University of Sao Paulo |
da Silva A.P.,University of Sao Paulo |
Giarola N.F.B.,State University of Ponta Grossa |
Tormena C.A.,State University of Maringá |
de Moraes Sa J.C.,UEPG
Revista Brasileira de Ciencia do Solo | Year: 2012
Mechanical chiseling has been used to alleviate the effects of compaction in soils under no-tillage (NT). However, its effect on the soil physical properties does not seem to have a defined duration period. The purpose of this study was to evaluate the behavior of the bulk density (BD) and degree of compaction (DC) at different soil depths, after chiseling in no-tillage, for one year. The experiment was performed in Ponta Grossa, Paraná State, Brazil, using an Oxisol (Rhodic Hapludox). Bulk density and DC were previously measured in an area under NT for 16 years, then immediately after chiseling (CHI) in May 2009, six months after chiseling (CHI6M) in October 2009 and one year after chiseling (CHI12M) in May 2010. In the layers 0.0-0.10, 0.10-0.20 and 0.20-0.30 m, there was a significant BD reduction CHI and a marked increase CHI6M. The BD values measured CHI12M were similar to those before tillage. Chiseling reduced the DC in the layers 0.0-0.10 m and 0.10-0.20 m, but returned to the initial values one year later. During the evaluation periods CHI, CHI6M and CHI12M, the BD increased in the layer 0.30-0.40 m, compared with NT. The highest DC values were observed six months after chiseling; nevertheless the structural recovery of the soil was considerable, possibly due to the high degree of soil resilience and the influence of the wetting and drying cycles detected in the study period. The chiseling effects, evaluated by BD and DC, lasted less than one year, i.e., the beneficial short-term effects of chiseling on the reduction of the surface BD increased the risk of compaction in deeper soil layers.
Canteri M.H.G.,Federal Technological University of Paraná |
Moreno L.,UEPG |
Wosiacki G.,UEPG |
De Scheer A.P.,Federal University of Paraná
Polimeros | Year: 2012
Pectin, probably the most complex macromolecule in nature is a hetero-polysaccharide containing predominantly residues of galacturonic acid (GalA). This polymer, which belongs to a group of dietary fibers, is widely used as a gelling agent and stabilizer in the food industry. The main industrial processing to obtain pectin is based on the solubilization of protopectin from apple pomace and citrus peels, which is done under low acidity and heated conditions. Recent studies have reported the extraction of pectin from new raw materials and using different extraction conditions, which influence the yield and quality of the final product, and may improve the rheological properties. This review describes the structure, sources, applications and industrial extraction processes, as well as the analysis methods of physicochemical characterization of pectin.
Caires E.F.,UEPG |
Maschietto E.H.G.,UEPG |
Garbuio F.J.,Instituto Federal Catarinense |
Churka S.,University of Sao Paulo |
Scientia Agricola | Year: 2011
The conditions in which a favorable response to a gypsum application can be expected on crop yields are not clear. A 3-year field trial was carried out to evaluate the effects of gypsum application on soil chemical attributes and nutrition and yield of corn (Zea mays L.) and soybean (Glycine max L. Merrill) on a clayey Typic Hapludox of high fertility and low acidity under no-till in Guarapuava, Parana State, Brazil. Treatments were arranged in a randomized complete block design with four replications, and consisted of gypsum application on the soil surface at 4, 8, and 12 Mg ha-1. Gypsum application increased the P content in the soil most superficial layer (0.0 - 0.1 m) and also the exchangeable Ca and S-SO42- contents and the Ca/Mg ratio in the soil profile (0.0 - 0.6 m). Gypsum also caused leaching of Mg and K exchangeable in the soil. An increase in Ca concentrations in the corn leaves, and in P and S concentrations in the corn and soybean leaves occurred following the gypsum application. A yield response of corn to initial application of gypsum was found, but subsequent soybean crops did not respond. Gypsum application proved to be an effective practice to maximize no-till corn grain yield.
Henneberg L.,Federal University of Paraná |
Jaccoud Filho D.S.,UEPG |
Ruaro L.,Federal University of Paraná |
Panobianco M.,Federal University of Paraná
Revista Brasileira de Sementes | Year: 2012
Most soybean pathogens are seed transmitted, deserving emphasis the fungus Sclerotinia sclerotiorum, which has been presenting worrying levels of field incidence in some soybean cropping areas in several Brazilian states. The objective of this study was to verify the efficiency of different methods for detecting S. sclerotiorum on soybean seeds artificially infected in the laboratory and from field production areas with a historical disease incidence. Seed samples of seven different cultivars collected from naturally infested fields, and one seed sample artificially inoculated in the laboratory were used. The following detection methods recommended in the literature were compared: Blotter test at 7°C, 14°C, and 21°C; Rolled Paper; and Neon-S. Results demonstrated that these methods showed no repeatability and had a low sensitivity for detecting the pathogen in seeds from areas with disease incidence. They were effective, however, for its detection on artificially inoculated seeds. In the Blotter test method at 7°C, there was a lower incidence of other fungi considered undesirable during seed analysis.
Milleo M.V.R.,UEPG |
Cristofoli I.,Academica do Curso de Agronomia
Scientia Agraria | Year: 2015
In order to evaluate soybean response to the ammoniacal zinc acetate (ACA Plus) application via seed, three trials were developed in different experimental fields during the seasons of 2012/13, 2013/14 and 2014/15, in the respective cities: Cornélio Procópio, Palmeira and Ponta Grossa. The design was in randomized blocks, with 5 treatments and 4 replications. The treatments were: 1) Absolute control (without any fertilizer and without treatment seeds); 2) Control (without seeds treatment); 3) ACA Plus - nitrogen source + zinc (2 mL kg-1 seed); 4) ACA Plus (4 mL kg-1 seed); 5) FortSeedDry - cobalt+molybdenum (2 g kg-1 seed). From the average obtained from the three seasons data's, it was reported that with the application of ACA Plus, compared to the application of cobalt and molybdenum, there were significant increases for: plant height, roots fresh and dry matter, number of pods per plant. Consequently, the highest yields were obtained by applying the ACA Plus. The application of ACA Plus via seeds is a practicable technique that can improve the final stand of the soybean crop.
Floresta | Year: 2013
This research aims to analyze the performance of the Brazilian pulp and paper industry, from 2001 to 2011, towards the main variables for the sector analysis, such as production capacity, sort of products, magnitude of exports, imports, destination of exports, level and capacity of utilization, and the average price of exports. In order to that, it used primary data from Ministry of Development, Industry and Foreign Trade (MDIC, 2012), Brazilian Association of Pulp and Paper (BRACELPA, 2011) and Food and Agriculture Organization of the United Nations (FAO, 2011). In general, results indicate that cellulose industry has gained importance in international trade, before a new spatial redistribution of production, according to the obsolescence of European, North American and Canadian industries, and the insertion of hardwood pulp in different stages of production. In relation to the paper industry, the results suggest a scenario not as promising as for the pulp one, even though domestic market may constitute a major boost to the industry.