Evaluating the potential of high pressure high temperature and thermal processing on volatile compounds, nutritional and structural properties of orange and yellow carrots

The present study compares the impact of thermal and high pressure high temperature(HPHT) processing on volatile profile (via a non-targeted headspace fingerprinting) and structural and nutritional quality parameter (via targeted approaches) of orange and yellow carrot purees. The effect of oil enrichment was also considered. Since oil enrichment affects compounds volatility, the effect of oil was not studied when comparing the volatile fraction. For the targeted part, as yellow carrot purees were shown to contain a very low amount of carotenoids, focus was given to orange carrot purees. The results of the non-targeted approach demonstrated HPHT processing exerts a distinct effect on the volatile fractions compared to thermal processing. In addition, different colored carrot varieties are characterized by distinct headspace fingerprints. From a structural point of view, limited or no difference could be observed between orange carrot purees treated with HPHT or HT processes, both for samples without and with oil. From nutritional point of view, only in samples with oil, significant isomerisation of all-trans-β-carotene occurred due to both processing. Overall, for this type of product and for the selected conditions, HPHT processing seems to have a different impact on the volatile profile but rather similar impact on the structural and nutritional attributes compared to thermal processing.

The effect of the degree of hydrolysis of the PVA and the plasticizer concentration on the color, opacity, and thermal and mechanical properties of films based on PVA and gelatin blends

The objective of this work was to study the color, opacity, crystallinity, and the thermal and mechanical properties of films based on blends of gelatin and five different types of PVA [poly(vinyl alcohol)], with and without a plasticizer. The effect of the degree of hydrolysis of the PVA and the glycerol concentration on these properties was studied using colorimetry, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and tensile mechanical tests. All films were essentially colorless (Delta E* < 5) and with low opacity ( Y <= 2.1). The DSC results were typical of partially crystalline materials, showing some phase separation characterized by a glass transition (T(g) = 40-55 degrees C), related to the amorphous part of the material, followed by two endothermic peaks related to the melting (T(m) = 100-160 and 170-210 degrees C) of the crystallites. The XRD results confirmed the crystallinity of the films. The film produced with PVA Celvol((R)) 418 (DH = 91.8%) showed the highest tensile resistance (tensile strength = 38 MPa), for films without plasticizer. However, with glycerol, the above-mentioned PVA and the PVA Celvol((R)) 504 produced the least resistant films of all the PVA types. But, although the mechanical properties of the blended films depended on the type of PVA used, there was no direct relationship between these properties and the degree of hydrolysis of the PVA. The properties studied were more closely dependent on the glycerol concentration. Finally, the mechanical resistance of the films presented a linear relationship with the glass transition temperature of the films. (c) 2007 Elsevier Ltd. All rights reserved.

Thermal and structural properties of commercial dental resins light-cured with blue emitting diodes (LEDs)

We have investigated the thermal and structural properties of different commercial dental resins: Filtek(TM) Z-350, Grandio(A (R)), Tetric Ceram(A (R)), and TPH Spectrum(A (R)). The purpose of the present study was to evaluate quantitatively the photo-polymerization behavior and the effect of filler contents on the kinetic cures of the dental resins by using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. We have successfully obtained the low and high glass transition T (g) values of the dental composite resins from DSC curves. It was also observed a good agreement between the both T (g) values, activation energies from thermal degradation, and the degree of conversion obtained for all samples. The results have shown that Tetric Ceram(A (R)) dental resin presented the higher T (g) values, activation energy of 215 +/- A 6 KJ mol(-1), and the higher degree of conversion (63%) when compared to the other resins studied herein.

Radiation properties of coil-coated steel in building envelope surfaces and the influence on building thermal performance

Recent studies have shown that the optical properties of building exterior surfaces are important in terms of energy use and thermal comfort. While the majority of the studies are related to exterior surfaces, the radiation properties of interior surfaces are less thoroughly investigated. Development in the coil-coating industries has now made it possible to allocate different optical properties for both exterior and interior surfaces of steel-clad buildings. The aim of this thesis is to investigate the influence of surface radiation properties with the focus on the thermal emittance of the interior surfaces, the modeling approaches and their consequences in the context of the building energy performance and indoor thermal environment. The study consists of both numerical and experimental investigations. The experimental investigations include parallel field measurements on three similar test cabins with different interior and exterior surface radiation properties in Borlänge, Sweden, and two ice rink arenas with normal and low emissive ceiling in Luleå, Sweden. The numerical methods include comparative simulations by the use of dynamic heat flux models, Building Energy Simulation (BES), Computational Fluid Dynamics (CFD) and a coupled model for BES and CFD. Several parametric studies and thermal performance analyses were carried out in combination with the different numerical methods. The parallel field measurements on the test cabins include the air, surface and radiation temperatures and energy use during passive and active (heating and cooling) measurements. Both measurement and comparative simulation results indicate an improvement in the indoor thermal environment when the interior surfaces have low emittance. In the ice rink arenas, surface and radiation temperature measurements indicate a considerable reduction in the ceiling-to-ice radiation by the use of low emittance surfaces, in agreement with a ceiling-toice radiation model using schematic dynamic heat flux calculations. The measurements in the test cabins indicate that the use of low emittance surfaces can increase the vertical indoor air temperature gradients depending on the time of day and outdoor conditions. This is in agreement with the transient CFD simulations having the boundary condition assigned on the exterior surfaces. The sensitivity analyses have been performed under different outdoor conditions and surface thermal radiation properties. The spatially resolved simulations indicate an increase in the air and surface temperature gradients by the use of low emittance coatings. This can allow for lower air temperature at the occupied zone during the summer. The combined effect of interior and exterior reflective coatings in terms of energy use has been investigated by the use of building energy simulation for different climates and internal heat loads. The results indicate possible energy savings by the smart choice of optical properties on interior and exterior surfaces of the building. Overall, it is concluded that the interior reflective coatings can contribute to building energy savings and improvement of the indoor thermal environment. This can be numerically investigated by the choice of appropriate models with respect to the level of detail and computational load. This thesis includes comparative simulations at different levels of detail.

The Effect of Residence Time on the Tensile Properties of Superelastic and Thermal Activated Ni-Ti Orthodontic Wires

Since the 1980s, different devices based on superelastic alloys have been developed to fulfill orthodontic applications. Particularly in the last decades several researches have been carried out to evaluate the mechanical behavior of Ni-Ti alloys, including their tensile, torsion and fatigue properties. However, studies regarding the dependence of elastic properties on residence time of Ni-Ti wires in the oral cavity are scarce. Such approach is essential since metallic alloys are submitted to mechanical stresses during orthodontic treatment as well as pH and temperature fluctuations. The goal of the present contribution is to provide elastic stress-strain results to guide the orthodontic choice between martensitic thermal activated and austenitic superelastic Ni-Ti alloys. From the point of view of an orthodontist, the selection of appropriate materials and the correct maintenance of the orthodontic apparatus are essential needs during clinical treatment. The present work evaluated the elastic behavior of Ni-Ti alloy wires with diameters varying from 0.014 to 0.020 inches, submitted to hysteresis tensile tests with 8% strain. Tensile tests were performed after periods of use of 1, 2 and 3 months in the oral cavity of patients submitted to orthodontic treatment. The results from the hysteresis tests allowed to exam the strain range covered by isostress lines upon loading and unloading, as well as the residual strain after unloading for both superelastic and thermal activated Ni-Ti wires. Superelastic Ni-Ti wires exhibited higher load isostress values compared to thermal activated wires. It was found that such differences in the load isostress values can increase with increasing residence time.

Thermal and Rheological Properties of a Family of Botryosphaerans Produced by Botryosphaeria rhodina MAMB-05

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

Thermal study and physico-chemical characterization of some functional properties of guava seeds protein isolate (Psidium guajava)

The guava seed protein isolate ( PI) was obtained from the protein precipitation belonging to the class of the gluteline (Ip 4.5). The conditions for the preparation of the PI were determined by both the solubility curve and simultaneous thermogravimetry-differential thermal analysis (TG-DTA): pH 11.5, absence of NaCl and whiteners and T=( 25 +/- 3) degrees C. Under these conditions a yield of 77.0 +/- 0.4%, protein content of 94.2 +/- 0.3, ashes 0.50 +/- 0.05% and thermal stability, T= 200 degrees C, were obtained. The TG-DTA curves and the PI emulsification capacity study showed the presence of hydrophobic microdomains at pH 11.5 and 3.0 suggesting a random coil protein conformation and, to pH 10.0, an open protein conformation. The capacity of emulsification (CE), in the absence of NaCl, was verified for: 1 - pH 3.0 and 8.5, using the IP extracted at pH 10.0 and 11.5, CE >= 343 +/- 5 g of emulsified oil/g of protein; 2 - pH 6.60 just for the PI obtained at pH 11.5, CE >= 140 +/- 8 g of emulsified oil/g of protein.

The effect of thermal cycles on the mechanical properties of fiber-metal laminates

The effect of thermal-shock cycles on the mechanical properties of fiber-metal laminates (FMLs) has been evaluated. FML plates were composed by two AA2024 Al sheets (1.6 mm thick) and one composite ply formed by two layers of unidirectional glass fiber epoxy prepreg and two layers of epoxy adhesive tape of glass fiber reinforced epoxy adhesive. The set was manufactured by hand layup and typical vacuum bag technique. The curing cycle was in autoclave at 125 +/- 5 degrees C for 90 min and an autoclave pressure of 400 kPa. FML coupons taken from the manufactured plate were submitted to temperature variations between -50 and +80 degrees C, with a fast transition between these temperatures. Tensile and interlaminar shear strength were evaluated on samples after 1000 and 2000 cycles, and compared to nonexposed samples. 2000 Cycles corresponds to typical C Check interval for commercial aircraft maintenance programs. It was observed that the thermal-shock cycles did not result in significant microstructural changes on the FML, particularly on the composite ply. Similarly, no appreciable effect on the mechanical properties of FML was observed by the thermal-shock cycles. (c) 2012 Elsevier Ltd. All rights reserved.

Influence of thermal annealing treatment in oxygen atmosphere on grain boundary chemistry and non-ohmic properties of SnO2 center dot MnO polycrystalline semiconductors

The present work studied the influence of thermal treatment in oxygen rich atmosphere on heterogenous junctions in Mn-doped SnO2 polycrystalline system presenting varistor behavior. The samples were prepared by conventional oxide mixture methodology, and were submitted to heat treatment in oxygen rich atmosphere at 900 degrees C for 2h. The samples were characterized by X-ray diffraction, scanning electron microscopy, dc and ac electrical measurements. The results showed that there is an evident relationship between the microstructure heterogeneity and non-ohmic electrical properties. It was found that for this SnO2 center dot MnO-based varistor system the heat treatment in oxygen rich atmosphere does not necessarily increase the varistors properties, which was related to the decrease in the grain boundary resistance. The results are compared with Co-doped SnO2 varistors and ZnO based varistors. (C) 2008 WILEY-VCH Verlay GmbH & Co. KGaA, Weinheim.

PHYSICAL PROPERTIES of TELLURITE GLASSES PREPARED UNDER DIFFERENT THERMAL HISTORIES

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermal and pasting properties of cassava starch-dehydrated orange pulp blends

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Red Mud from Brazil: Thermal Behavior and Physical Properties

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

Thermal, structural and optical properties of new tungsten lead-pyrophosphate glasses

Crystalline lead-pyrophosphate precursor was prepared in aqueous solution from lead nitrate and phosphoric acid and characterized by X-ray diffraction, thermogravimetry and Raman scattering. This crystalline lead-phosphate was then used to prepare glass samples in the binary system Pb(2)P(2)O(7)-WO(3). Dependence of WO(3) content on thermal, structural and optical properties were investigated by thermal analysis (DSC), Raman spectroscopy, UV-visible and near-infrared absorption and M-Line technique to access refractive index values. Incorporation of WO(3) in the lead-pyrophosphate matrix enhances the glass transition temperature and thermal stability against devitrification, favors formation of P-O-W bonds and WO(6) clusters. In addition, optical properties are strongly modified with a redshift of the optical bandgap with WO(3) incorporation as well as an increase of the refractive index from 1.89 to 2.05 in the visible. (C) 2011 Elsevier B.V. All rights reserved.

Effect of addition of different hydrocolloids on pasting, thermal, and rheological properties of cassava starch

Amidos e gomas são hidrocoloides frequentemente usados em sistemas alimentícios com a finalidade de fornecer textura, umidade e mobilidade de água. A interação amido-goma em sistemas alimentícios pode alterar o inchamento do grânulo de amido e as suas propriedades de gelatinização e reológicas. Neste trabalho, o efeito da adição de goma xantana (GX), carboximetilcelulose sódica (CMC) e carragena (CAR) nas concentrações de 0,15, 0,25, 0,35 e 0,45% (p/v) sobre as propriedades de pasta, térmicas e reológicas do amido de mandioca foi estudado. O Poder de inchamento (PI) e a Microscopia Eletrônica de Varredura (MEV) dos géis de amido também foram avaliados. Os resultados obtidos mostraram que a GX apresentou forte interação com o amido, penetrando entre os grânulos e provocando aumento das viscosidades de pasta, PI, G' e G, e redução da retrogradação do amido; CMCS aumentou as viscosidades de pasta, PI, G' e G das misturas, principalmente em função da sua maior capacidade de reter água, e não por causa da interação com o amido; CAR não modificou qualquer das propriedades do amido, porque não houve nenhuma interação entre essa goma e o amido de mandioca nas concentrações usadas.

Thermal and mechanical properties of PVDF/PANI blends

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