Eletrodinâmica de ordem superior em (2+1)D

Pós-graduação em Física - IFT

Dinâmica de campos escalares fora do equilíbrio

Pós-graduação em Física - IFT

Structural and Electric-Optical Properties of Zinc Phthalocyanine Evaporated Thin Films: Temperature and Thickness Effects

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

NUMERICAL SIMULATION of CONVECTION-DIFFUSION PROBLEMS BY THE CONTROL-VOLUME-BASED FINITE-ELEMENT METHOD

This work presents a numerical study of the tri-dimensional convection-diffusion equation by the control-volume-based on finite-element method using quadratic hexahedral elements. Considering that the equation governing this problem in its main variable may represent several properties, including temperature, turbulent kinetic energy, viscous dissipation rate of the turbulent kinetic energy, specific dissipation rate of the turbulent kinetic energy, or even the concentration of a contaminant in a given medium, among others, the wide applicability of this problem is thus evidenced. Three cases of temperature distributions will be studied specifically in this work, in addition to one case of pollutant dispersion upon analysis of the concentration of a contaminant in a fixed flow point. Some comparisons will be carried out against works found in the open literature, while others will be done according to each phenomenon characteristics.

FLOW PROPERTIES and TUBE FRICTION FACTOR of MILK CREAM: INFLUENCE of TEMPERATURE and FAT CONTENT

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

Thermophysical Properties of Lemon Juice as Affected by Temperature and Water Content

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

Temperature dependence of dielectric properties for Ba(Zr0.25Ti0.75)O-3 thin films obtained from the soft chemical method

Ba(Zr0.25Ti0.75)O-3(BZT) thin films prepared by the polymeric precursor method (PPM) were annealed at 500, 600, and 700 degrees C for 4h. All films crystallized in the perovskite structure present a crack-free microstructure. Dielectric properties of the BZT thin films were investigated as a function of frequency and applied voltage. The dielectric constant of the films were 36, 152 and 145 at 1 kHz, while the dielectric loss were 0.08, 0.08, and 0.12 at 1 MHz. (c) 2007 Elsevier B.V. All rights reserved.

Study of structural evolution and photoluminescent properties at room temperature of Ca(Zr, Ti)O-3 powders

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermophysical and rheological properties of dulce de leche with and without coconut flakes as a function of temperature

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

Influence of temperature on the properties of the xylanolytic enzymes of the thermotolerant fungus Aspergillus phoenicis

This study reports on the effects of growth temperature on the secretion and some properties of the xylanase and beta-xylosidase activities produced by a thermotolerant Aspergillus phoenicis. Marked differences were observed when the organism was grown on xylan-supplemented medium at 25 degreesC or 42 degreesC. Production of xylanolytic enzymes reached maximum levels after 72 h of growth at 42 degreesC; and levels were three- to five-fold higher than at 25 degreesC. Secretion of xylanase and beta-xylosidase was also strongly stimulated at the higher temperature. The optimal temperature was 85 degreesC for extracellular and 90 degreesC for intracellular beta-xylosidase activity, independent of the growth temperature. The optimum temperature for extracellular xylanase increased from 50 degreesC to 55 degreesC when the fungus was cultivated at 42 degreesC. At the higher temperature, the xylanolytic enzymes produced by A. phoenicis showed increased thermo stability, with changes in the profiles of pH optima. The chromatographic profiles were distinct when samples obtained from cultures grown at different temperatures were eluted from DEAE-cellulose and Biogel P-60 columns.

Temperature and water content influence on thermophysical properties of coffee extract

Specific heat, thermal conductivity, thermal diffusivity, and density of coffee extract were experimentally determined in the range of 0.49 to 0.90 (wet basis) water content and at temperatures varying from 30 to 82 degreesC. Thermal conductivity and specific heat were measured by means of the same apparatus- a cell constituted of two concentric cylinders - operating at steady and unsteady state, respectively. The thermal diffusivity was measured by the well-known Dickerson's method and density was determined by picnometry. The results obtained were used to derive mathematical models for predicting these properties as a function of concentration and temperature.

Structural and electrical properties of SrBi2Nb2O9 thin films prepared by chemical aqueous solution at low temperature

SrBi2Nb2O9 (SBN) thin films were prepared by the polymeric precursors method and deposited by dip coating onto Pt/Ti/SiO2/Si(100) substrates. The dip-coated films were specular and crack-free and crystallized during firing at 700 degrees C. Microstructure and morphological evaluation were followed by grazing incident X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films exhibited somewhat porous grain structure with rounded grains of about 100 nm. For the electrical measurements, gold electrodes of 300 mu m in diameter were sputter deposited on the top surface, forming a metal-ferroelectric-metal (MFM) configuration. The remanent polarization (P-r) and coercive field (E-c) were 5.6 mu C/cm(2) and 100 kV/cm, respectively. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Influence of temperature and water and fat contents on the thermophysical properties of milk

Heat capacity, thermal conductivity, and density of whole milk, skimmed milk, and partially skimmed milk were determined at concentrations varying from (72.0 to 92.0) mass % water content and from (0.1 to 7.8) mass % fat content, at temperatures ranging from (275.15 to 344.15) K. Heat capacity and thermal conductivity varied from (3.4 to 4.1) J(.)g(-) K-1.(-1) and from (0.5 to 0.6) W(.)m(-1) K-1.(-1), respectively. Density varied from (1011.8 to 1049.5) kg(.)m(-3). Polynomial functions were used to model the dependence of the properties upon the studied variables. A linear relationship was obtained for all the properties. In the tested range, water content exhibited a greater influence on the properties, while fat content showed a smaller influence.

Temperature dependence of electron properties of Sn doped In2O3 nanobelts

This paper reports on the measurements of transport properties of high crystalline quality Sn doped In2O3 nanobelts. The samples presented metallic conduction in a large range of temperatures; however, at low temperatures, the resistivity showed a slight increase and the current-voltage curves showed a tendency to saturate even in the low-voltage range. From these observations, we discuss some arguments on the possibility of low dimensional conducting channels as the main responsible for the conduction at low temperatures. Additionally, we present an alternative technique for production of low resistance ohmic contacts, which can be further used in devices' construction. (C) 2007 Elsevier B.V. All rights reserved.

Influence of temperature on the microstructure and electrical properties of BBT thin films

The BBT films were prepared by a spin-coating process from the polymeric precursor method (Pechini process). In order to study the influence of the temperature on the BBT microstructure and electrical properties, the films were deposited on platinum coated silicon substrates and annealed from 700degreesC to 800degreesC for 2 hours in oxygen atmosphere. The crystallinity of the films was examined by X-ray diffraction while the surface morphology was analysed by atomic force microscope. The dielectric properties and dissipation factor of BaBi2Ta2O9 films at 1 MHz were observed. The polarization-electric field hysteresis loops revealed the ferroelectric characteristics of BaBi2Ta2O9 thin films.