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Desenvolvimento, caracterização e secagem de sementes com cobertura artificial
(Universidade Federal de São Carlos, 2003-12-11) Ferreira, Margarete Martins Pereira; Sartori, Dermeval José Mazzini
The studies on the preparation and drying of seeds with artificial coat covering promote the integration of the referring research lines for drying of seeds and gel. Thus, the aim of this research were carried out a methodology to promote the coated of seeds with material the base of gel, to characterize the system seed-gel and to realize the search of information about the interaction among particles and fluid during the drying process in a fixed bed. In addition, it was also analyze, before and after each accomplished operation, the effects of the stages involved in the construction of the coated seed on the physiologic quality of them. Millet seeds (Pennisetum glaucum), gel agar and sorbitol were used in the tests. The best mixture was used to coat seeds in order to maintain their physiologic quality and the gel adherence. To them was composed such mixture by 1.5% of gel agar and by 5% of sorbitol in relation to the gel. After the development of the methodology of coating, some analyses were used to characterize the system seed-gel such as: dimensions, sphericity, specific mass, thermal conductivity, thermal diffusivity and specific heat. Due to the high moisture content of the coating material, it was necessary the development of a methodology that accelerated the moisture transfer, for the determination of the equilibrium moisture content of the system seed-gel-air. The best equation to determine the equilibrium of the system it was Chen-Clayton s equation, which presented a good agreement with the experimental data, in the range of temperatures from 25 to 50°C and moisture from 11 to 84% bu. The drying kinetics was obtained in fixed bed of thick layer for temperatures from 30 to 50°C and velocities from 0.5 to 2.5 m/s, The equation fitted the experimental data of drying kinetics better was one proposed by Page. . Tests of convective drying in fixed of thick layer allowed obtaining the maxim thickness of bed to supplies appropriate product to the storage. The immediate and latent effects were evaluated and according to them, the physiologic quality was maintained. Therefore, the system seed-gel satisfied the expectations concern with tests of physical characterization and regeneration of the seeds. However, this system seed-gel was also appropriate for convective drying process in fixed bed of small thickness.
Plasticidade fenotípica em indivíduos jovens de Aloysia virgata (Ruiz et Pav.)
(Universidade Federal de São Carlos, 2003-12-11) Corrêa, Izabel Pimenta; Prado, Carlos Henrique Britto de Assis; https://lattes.cnpq.br/7561749470600567
Phenotypic plasticity in a tree species Aloysia virgata was investigated on seedlings growing under two different natural irradiance conditions: under full solar irradiance (FS) and in shade under tree forest canopy (UC). Seedlings with 180 days old cultivated under FS showed significant (p<0.001, n=12) larger average values of biometrics (height, diameter of stem, number of leaves and total leaf area), and biomass (root, stem, and leaves) parameters. Carboxilation efficiency (CE), and potential photosynthetic capacity (on mass or on area bases) were greater in seedlings that grew under FS. In addition, the instantaneous nutrient use efficiency determined to N, P, K, Ca, Mg, and S in curves of net photosynthesis as a function of substomatal CO2 concentration, and the water use efficiency (between photosynthetic active radiation greater than 250 µmol m-2 s-1) were higher in individuals under FS. Only the root/shoot ratio average value was greater in shade condition. In spite of Aloysia virgata showed greater average values of biometric, biomass, and gas exchange parameters under FS, all UC individuals survived during 36 months. The high phenotypic plasticity showed under contrasting irradiance was brought about by changes in several organization levels of the plant, from mesophyll tissue (CE) until whole plant (biomass allocation). The high phenotypic plasticity exhibited by Aloysia virgata can explain, at least in part, its vast distribution in several ecosystem and successional stages in South America.
Estudo de caso sobre a medição de desempenho da cadeia de suprimentos de uma montadora de autoveículos
(Universidade Federal de São Carlos, 2003-12-11) Jesus, Giancarlo Pessoa de; Martins, Roberto Antonio; https://lattes.cnpq.br/3518820028045730