Effect of Ag concentration on the thermal behavior of the Cu-10 mass% Al and Cu-11 mass% Al alloys

In this work the effect of Ag concentration on the thermal behavior of the Cu-10 mass% Al and Cu-11 mass% Al alloys with additions of 4, 6, 8 and 10 mass% Ag was studied using differential scanning calorimetry (DSC), in situ X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results showed that for the Cu-10 mass% Al alloy Ag addition induce the beta'(1) phase formation and for the Cu-11 mass% Al alloy these additions increase the amount of martensite formed on quenching and decrease the stability range of this phase on heating.

Study on the thermal behavior of the complexes of the type [PdX2(tdmPz)] (X = Cl-, Br-, I-, SCN-)

Four new mononuclear Pd(II) complexes of the type [PdX2(tdmPz)] {X = Cl- (1); Br- (2); I- (3); SCN- (4); tdmPz = 1-thiocarbamoyl-3,5-dimethylpyrazole} have been synthesized and characterized by elemental analysis, IR spectroscopy, H-1 and C-13{H-1}-NMR experiments. The thermal behavior of the complexes 1-4 has been investigated by means of thermogravimetry (TG) and differential thermal analysis (DTA). From the initial decomposition temperatures, the thermal stability of the complexes can be ordered in the sequence: 3 < 4 a parts per thousand 2 < 1. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.

Thermal behavior of the Cu-22.55 at.%Al alloy with small Ag additions

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

Thermal behaviour of malonic acid, sodium malonate and its compounds with some bivalent transition metal ions

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

Thermal behaviour of corn starch granules under action of fungal alpha-amylase

Corn starch, partially hydrolyzed by fungal alpha-amylase was investigated by using thermal analysis, microscopy and X-ray diffraction. After enzymatic treatment lower degradation onset temperatures were observed. DSC analysis showed almost similar range of gelatinization temperature, however, the enthalpies of gelatinization increased for the partially hydrolyzed starch granules. According to the X-ray diffraction analysis, stronger cereal pattern peaks were recognized after enzymatic digestion. The results suggested that the hydrolysis was more pronounced in the amorphous part of the starch granules.

Thermal behaviour of fumaric acid, sodium fumarate and its compounds with light trivalent lanthanides in air atmosphere

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

Evaluation of the thermal diffusivity of vegetable oils during frying by Thermal Lens Spectrometry

In this work we report on the use of the Thermal Lens method to verify the evolution of the thermal diffusivity of sunflower and soybean vegetable oils utilized in preparation of twenty five snacks portions. Our results show that the thermal diffusivity for sunflower oil does not change between 1 and 25 portions of fried snacks. By another hand, the soybean thermal diffusivity exhibits a little decrease for higher portion of fried snacks, indicating that for this oil the triglyceride level is reduced as a degradation process.

Thermal study of mononuclear Pd(II) complexes of the type [Pd(X)(2)(Rtu)(PPh3)] (X = Cl, SCN; Rtu = N-methylthiourea, N-phenylthiourea)

The synthesis, spectroscopic characterization, and thermal analysis of the compounds [Pd(X)(2)(mtu)(PPh3)] (X = Cl- (1), SCN- (2); mtu = N-methylthiourea; PPh3 = triphenylphosphine) and [Pd(X)(2)(phtu)(PPh3)] (X = Cl- (3), SCN- (4); phtu = N-phenylthiourea) are described. The thermal decomposition of the compounds occurs in two, three, or four stages and the final decomposition products were identified as Pd-0 by X-ray powder diffraction. The thermal stability order of the complexes is 4 > 3 > 2 > 1.

Viscoelastic and Thermal Properties of Collagen-Xanthan Gum and Collagen-Maltodextrin Suspensions During Heating and Cooling

The purpose of this work was to investigate the viscoelastic properties of aqueous suspensions of crude collagen powder extracted from bovine hides and nonsubmitted to the hydrolysis reaction that leads to gelatin. The studied variables included the collagen concentration and the addition of xanthan gum or maltodextrin at varied concentrations during heating/cooling of the mixtures. Differential scanning calorimetry thermograms showed that the addition of polysaccharides decreased the endothermic peak areas observed at the denaturation temperature of collagen. The rheological properties of the pure collagen suspensions were highly dependent on concentration: 4% and 6% collagen suspensions presented a great increase in the storage modulus after heating/cooling, whereas for concentrations of 8% and 10% G' decreased during heating and did not recover its original value after heating/cooling. The frequency sweeps showed that the thermal treatment was responsible by the strengthening of the interactions that formed the polymer network. Addition of 0.1% xanthan gum to collagen suspensions increased the gel strength, especially after heating/cooling of the system, whereas increasing gum concentration to 0.3% resulted in a weaker gel, which could indicate thermodynamic incompatibility between the biopolymers. Mixtures of collagen and maltodextrin resulted in more fluid structures than those obtained with pure collagen at the same collagen concentration and the range of temperatures in which these mixtures behaved as a gel decreased with increasing concentrations of both collagen and maltodextrin, suggesting incompatibilities between the biopolymers.

Synthesis, characterization and thermal behaviour of solid 2-methoxybenzoates of trivalent metals

Solid-state Ln(L)(3) compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and L is 2-methoxybenzoate have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information on the composition, dehydration, coordination mode, structure, thermal behaviour and thermal decomposition.

Synthesis, characterization and thermal behaviour of light trivalent lanthanides folates on solid state

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

Thermal investigation of solid 2-methoxycinnamylidenepyruvate of some bivalent transition metal ions

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

Preparation and thermal characterization of inclusion complex of Brazilian green propolis and hydroxypropyl-beta-cyclodextrin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Synthesis, characterization and thermal behaviour of solid-state 3-methoxybenzoates of heavy trivalent lanthanides and yttrium(III)

Solid-state Ln(L)(3) compounds, where Ln stands for trivalent Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and L is 3-methoxybenzoate, have been synthesized. X-ray powder diffractometry, infrared spectroscopy, complexometry and elemental analysis were used to characterize the compounds. In order to study the thermal behaviour of these compounds simultaneous thermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC) were used. The results provided information on the composition, dehydration, polymorphic transformation, thermal stability and thermal decomposition of the synthesized compounds.

Influence of Ag addition on the thermal behavior of the Cu-11 mass% Al alloy

In this work the influence of Ag additions on the thermal behavior of the Cu-11 mass% Al alloy was studied using differential scanning calorimetry, in situ X-ray diffractometry and scanning electron microscopy. The results indicated that changes in the heating rate shift the peak attributed to alpha phase formation to higher temperatures, evidencing the diffusive character of this reaction. The activation energy value for the alpha phase formation reaction, obtained from a non-isotherm kinetic model, is close to that corresponding to Cu atoms self diffusion, thus confirming that this reaction is dominated by Cu atoms diffusion through the martensite matrix.