Investigation of the structural, optical and dielectric properties of highly (100)-oriented (Pb0.60Ca0.20Sr0.20)TiO3 thin films on LaNiO3 bottom electrode

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

Experimental evidence of enhanced ferroelectricity in Ca doped BiFeO3

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Synthesis by a chemical method and characterization of CaZrO3 powders: Potential application as humidity sensors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Lead-free BaBi4Ti4O15 ceramics: Effect of synthesis methods on phase formation and electrical properties

The processing of ferroelectric BaBi4Ti4O15 (BBT) ceramics from powders prepared by conventional solid state reaction (SSR) and mechanochemical activation (MA) has been investigated. It was shown that MA synthesis reduces the synthesis temperature of BBT powders, leading to smaller particles with reduced anisotropy and consequently to smaller grain size of ceramics. Dielectric properties were investigated in a wide range of temperatures (20-800 degrees C) and frequencies (1.21 kHz to 1 MHz). The relative dielectric permittivity at Curie temperature was higher for solid state obtained ceramics than for the mechanically treated ones. The conductivity of sintered samples was studied, suggesting decreasing of conductivity of BBT-MA in comparison with BBT-SS ceramics. The influence of the grain and the grain boundaries contribution to the dielectric behavior in both ceramics was analyzed through impedance spectroscopy. A well-defined ferroelectric hysteresis loop was obtained for both samples. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Structural, dielectric, ferroelectric and optical properties of PBCT, PBST and PCST complex thin films on LaNiO3 metallic conductive oxide layer coated Si substrates by the CSD technique

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

Physical properties of self-polarized PZT thin films at compositions around the morphotropic phase boundary

The physical properties of self-polarized PbZr1-xTixO3 thin films with no preferential orientation in a range of compositions 0.46 <= x <= 0.50 were investigated. Structural analysis revealed the coexistence of monoclinic-tetragonal and monoclinic-rhombohedral phases at compositions 0.46 <= x <= 0.49, where the monoclinic phase was in the majority and both the tetragonal and the rhombohedral phases in the minority. The dielectric permittivity (epsilon'= 447) reached its maximum at around composition x = 0.48. Asymmetries in the macroscopic and local hysteresis loops confirmed the existence of the self-polarization effect in the studied films.

Potentially synbiotic fermented beverage with aqueous extracts of quinoa (Chenopodium quinoa Willd) and soy

The aim of this study was to develop a potentially synbiotic beverage fermented with Lactobacillus casei LC-1 based on aqueous extracts of soy and quinoa with added fructooligosaccharides (FOS). Five formulations with differing proportions of soy and quinoa extracts were tested. The viability of the microorganism, the pH, and the acidity of all formulations were monitored until the 28th day of storage at 5 ℃. The chemical composition of the extracts and beverages and the rheological and sensory properties of the final products were analyzed. Although an increase in acidity and a decrease in pH were observed during the 28 days of storage, the viability of the probiotic microorganism was maintained at 10(8) CFU·mL(-1) in all formulated beverages throughout the storage period. An increase in viscosity and consistency in the formulations with higher concentrations of quinoa (F1 and F2) was observed. Formulation F4 (70% soy and 30% quinoa extracts) showed the least hysteresis. Formulations F4 and F5 (100% soy extract) had the best sensory acceptance while F4 resulted in the highest intention to purchase from a group of 80 volunteers. For chemical composition, F3 (50% soy and 50% quinoa extracts) and F4 showed the best results compared to similar fermented beverages. The formulation F4 was considered the best beverage overall.

Magnetically separable polymer (Mag-MIP) for selective analysis of biotin in food samples

This work presents an efficient method for the preparation of magnetic nanoparticles modified with molecularly imprinted polymers (Mag-MIP) through core-shell method for the determination of biotin in milk food samples. The functional monomer acrylic acid was selected from molecular modeling, EGDMA was used as cross-linking monomer and AIBN as radical initiator. The Mag-MIP and Mag-NIP were characterized by FTIR, magnetic hysteresis, XRD, SEM and N2-sorption measurements. The capacity of Mag-MIP for biotin adsorption, its kinetics and selectivity were studied in detail. The adsorption data was well described by Freundlich isotherm model with adsorption equilibrium constant (KF) of 1.46 mL g(-1). The selectivity experiments revealed that prepared Mag-MIP had higher selectivity toward biotin compared to other molecules with different chemical structure. The material was successfully applied for the determination of biotin in diverse milk samples using HPLC for quantification of the analyte, obtaining the mean value of 87.4% recovery.

Harmful oral suction habits in children: association with breastfeeding and family social profile

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Development, physical-chemical stability and rheological behavior of silicones formulations containing Dimethylaminoethanol (DMAE)

The aim of this paper was to develop formulations increased of DMAE and evaluate their physical-chemical stability and rheological behavior. Eleven formulations containing 3% DMAE pidolate or 3% DMAE acetamidobenzoate were developed and both preliminary stabilities tests and rheological measurements were carried out. They were considered stable during all period of study. The type of DMAE did not modify the viscosity of the emulsion and all presented pseudoplastic behavior with hysteresis area. An increase of hysteresis area could be observed with DMAE addition. The results point that the type of DMAE can influence the physical stability of the final product.

Variação da resistividade elétrica para três solos não saturados

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

Synthesis, structure and magnetic properties of Y3Fe5-xAlxO12 garnets prepared by the soft chemical method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of Electrical Resistivity in a Tropical Sandy Soil Compacted

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

Shear strength of a natural and compacted tropical soil

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

Temperature Effects on Suction Measurement Using the Filter Paper Technique

This paper presents the results of an experimental study of thermal effects on filter paper calibration curves used to obtain the soil suction. When the temperature is significantly different from ambient values, it is essential to consider the influence of temperature on the filter paper calibration curves to obtain a reliable soil suction measurement. The calibration curve of Whatman No. 42 filter paper was determined at 10 degrees C, 25 degrees C, and 50 degrees C using the vapor equilibrium technique with sodium chloride solutions at different concentrations and the axis translation technique. The experimental results showed a major influence of temperature on the filter paper calibration curves. Using the obtained experimental data a calibration equation was proposed, taking into account the effect of temperature. The obtained calibration curves were then used to determine the soil water retention curve of kaolin clay, which showed lower retention capacity at higher temperatures.