Anelastic spectroscopy in superconducting oxides

Since the discovery of the high Tc superconductors, several works have been made about the different properties of these materials. Anelastic spectroscopy experiments are sensitive tools to the study of defects in solids and phase transitions. By this technique, we can distinguish the different types of atomic jumps that happen to different temperatures. The intensity of the peaks in the anelastic spectrum and the step in the torsional modulus are related with the concentration of the relaxing entities, and the position of the peaks is determined by its mobility. In this paper, the study on Bi and Sm based superconducting oxides was made by anelastic relaxation measurements using a torsion pendulum. The samples were submitted to successive thermal treatments in high vacuum, in the temperature range between 100 K and 650 K, heating rate about 1 K/min. For Bi based superconducting oxides the results shown two peaks, that were associated to interstitial oxygen mobility and to orthorhombic to monoclinic phase transition. For Sm based superconducting oxides the results shown a relaxation peak that was attributed to the jumps of the oxygen atoms in the inter-chains O1 and 05 of the lattice.

Anelastic relaxation due to interstitial solutes diffusion in Nb and Nb-1 wt% Zr

Metals and alloys containing solute atoms dissolved interstitially often show anelastic behavior due to a process know as stress-induced ordering. The application of mechanical spectroscopy measurements to diffusion studies in body-centered cubic metals has been extensively used in the last decades. However the kind of preferential occupation of interstitial solutes in body-centered cubic metals is still controversial. The anelastic properties of the Nb and Nb-1 wt% Zr polycrystalline alloys were determined by internal friction and oscillation frequency measurements using a torsion pendulum inverted performed between 300K and 650K, operating in a frequency oscillation in the hertz bandwidth. The interstitial diffusion coefficients of oxygen and nitrogen in Nb and Nb-1 wt% Zr samples were determined at two distinct conditions: (a) for low concentration of oxygen and (b) for high concentration of oxygen.

Fig tree orchard formation using organic fertilization

The present work aimed at evaluating the effects of cattle manure fertilization on the growth and yield of fig trees. The cultivar 'Roxo de Valinhos' was used. One-, two-, three-and four-year-old trees were treated with cattle manure containing 0, 25, 50, 75, 100, 125 and 150% of the recommended nitrogen level per plant. The experiment was carried out using randomized blocks with 7 treatments, 5 replicates and 5 plants per experimental plot. The evaluated characteristics were: plant height, stem diameter, secondary branch length and diameter, yield per plant (kg plant-1), besides some quality characteristics of fruits such as pH, titratable acidity, soluble solids and texture. Manure application enhanced plant growth and fruit production. Significant differences were observed only for soluble solids content, pH and texture, which varied according to the crop cycle. After four crop cycles (2002/03, 2003/04, 2004/05 and 2005/06), the best results (about 5.0 kg of fruits per plant) were obtained with 100% of the recommended nitrogen dose, which corresponded to 14.3 kg of cattle manure per plant, in the last crop cycle (2005/2006).

Chemical and biochemical characterization of guava and araçá fruits from different regions of Brazil

Guava and araçá, species of the Psidium genus, are important options for Brazilian agribusiness, especially the former species, due to their fruit characteristics, such as appearance, taste and richness in minerals and phenolic compounds. These fruits can be consumed in natura or in several processed forms. The active germplasm bank is an important tool for genetic resource characterization and plant breeding studies. Sixty guava and ten araçá accessions of the Psidium active germplasm, sampled in 44 different Brazilian regions and grown at Embrapa Semiarid, were chemically and biochemically characterized in order to support breeding programs. The accessions were grown in a randomized block design, with two replications and three plants/plot. The sugar, proteins, soluble solids, titratable acidity, calcium, magnesium, iron and phosphorus contents were determined. Large variations were observed in the analyzed compounds, which could be attributed to the diversity of genotypes and also to the environmental conditions, which affect the plant metabolism. The high variability observed in most parameters of the accessions is an important factor for the improvement of these species. Most guava accessions showed higher titratable acidity and soluble solids than those found in commercial cultivars and, in araçá, these levels were even higher, which makes them promising for commercial exploitation. Moreover, fruits of the guava and araçá accessions present good sources of sugars and minerals. Special attention should be given to some guava and araçá accessions from Maranhão and Pernambuco States, respectively, which showed high levels for titratable acidity, soluble solids, SS/TA ratio, total soluble sugars, calcium, magnesium and iron, should be targets of breeding programs for new Psidium cultivars. © ISHS.

Caracterização morfológica e atributos de qualidade dos frutos de acessos de bananeira em clima subtropical

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conservação frigorificada de pêssegos ‘Tropic beauty’ irradiados com e sem utilização de permanganato de potássio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualidade de carambolas submetidas a diferentes tratamentos pós-colheita

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de genótipos de bananeira (Musa sp.) em Botucatu -SP

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

Atmosfera modificada e aplicação de cloreto de cálcio em caqui Giombo

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

Fenologia, produção e qualidade dos frutos de cultivares de mangueira em condições subtropicais

Pós-graduação em Agronomia (Horticultura) - FCA

Doses de potássio em cobertura na produção e qualidade de frutos de abobrinha-de-moita

Pós-graduação em Agronomia (Horticultura) - FCA

Processamento mínimo de melão tipo Orange Flesh e de melancia 'Crimson Sweet'

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Controle em pós-colheita de bolor verde em laranja pêra com microrganismos e tratamento térmico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Doses de N-Ureia e de esterco bovino na qualidade nutricional da alface em consórcio com a rúcula

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

Conservação de abacate ‘Hass’ e guacamole por irradiação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)