An influence of cooking on fatty acid composition in three varieties of common beans and in lentil

The fatty acid composition of three raw and cooked freeze-dried common bean varieties (Phaseolus vulgaris), namely enjevec, Semenarna 22 and Cipro, and of the lentil (Lens esculenta), var. Anicia, was determined and the influence of storage on their composition was studied. Analyses of fatty acid composition were conducted by in situ transesterification and capillary column gas-liquid chromatography. In raw milled beans average values of about 16% saturated fatty acids (SAT), 6% monosaturated fatty acids (MUFA) and 78% polyunsaturated fatty acids (PUFA) were found. Somewhat different values of 15% of SAT, 25% MUFA and 60% PUFA were found in lentil. In cooked beans the content of all fatty acids was slightly decreased. In cooked lentil the decrease was almost 50%, but the ratios of SAT, MUFA and PUFA in both cases were practically the same. After two years of storage at 4 °C the fatty acid content in raw milled beans was unchanged, but altered in cooked ones. The amounts of linoleic (18:2, n-6) and -linolenic (18:3, n-3) acid decreased, but myristic (14:0), margaric (17:0) and arachidic (20:0) acids increased. It was found that freeze-dried cooked beans, prepared from raw seed beans, kept 2.5 years at 10 °C, have practically the same fatty acid composition as freeze-dried cooked beans 0.5 year after harvesting.     

Chemical stability and electrical properties of Nb doped BaCe0.9Y0.1O3−δ as a high temperature proton conducting electrolyte for IT-SOFC

BaCe_0.9?xNb_xY_0.1O_3?δ (where x=0, 0.01, 0.03 and 0.05) powders were synthesized by solid-state reaction to investigate the influence of Nb concentration on chemical stability and electrical properties of the sintered samples. The dense electrolyte pellets were formed from the powders after being uniaxially pressed and sintered at 1550 °C. The electrical conductivities determined by impedance measurements in temperature range of 550–750 °C in different atmospheres (dry argon and wet hydrogen) showed a decreasing trend with an increase of Nb content. For all samples higher conductivities were observed in the wet hydrogen than in dry argon atmosphere. The chemical stability was enhanced with increasing of Nb concentration. It was found that BaCe_0.87Nb_0.03Y_0.1O_3?δ is the optimal composition that satisfies the opposite demands for electrical conductivity and chemical stability, reaching 0.8×10^?2 S cm^?1 in wet hydrogen at 650 °C compared to 1.01×10^?2 S cm^?1 for undoped electrolyte.     

Experimental Investigation and Thermodynamic Calculations of the Bi-Ge-Sb Phase Diagram

A phase diagram of the Bi-Ge-Sb ternary system was investigated experimentally by differential thermal analysis (DTA), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray powder diffraction (XRD) methods and theoretically by the CALPHAD method. The liquidus projection; invariant equilibria; and three vertical sections, Sb-Bi_0.5Ge_0.5, Ge-Bi_0.5Sb_0.5, and Bi-Ge_0.5Sb_0.5, as well as isothermal sections at 773 K and 373 K (500 °C and 100 °C), were predicted using optimized thermodynamic parameters for constitutive binary systems from the literature. In addition, phase transition temperatures of the selected samples with compositions along calculated isopleths were experimentally determined using DTA. Predicted isothermal sections at 773 K and 373 K (500 °C and 100 °C) were compared with the results of the SEM-EDS and XRD analysis from this work. In both cases, good agreement between the extrapolated phase diagram and experimental results was obtained. Alloys from the three studied vertical sections were additionally analyzed using the Brinell hardness test.     

Fluctuations in the Levels of Antioxidant Compounds and Antioxidant Capacity of Ten Small Fruits During One Year of Frozen Storage

The fluctuations in antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl, 2,2´-azinobis (3-ethylbenzthiazoline-6-sulphonic acid), and ferric reducing/antioxidant power assays), total phenol, total flavonoid, and total anthocyanin contents of 10 small fruits (sweet cherries, sour cherries, strawberries, red currants, raspberries, blackberries, hawthorn, cornelian cherries, and red and white grapes) were monitored during storage at ?20°C. After one year in storage, all varieties except hawthorn and white grapes retained equal or slightly greater total phenol content in comparison to the initial values. The total flavonoid and total anthocyanin levels also remained stable or even increased after 12 months in all fruits exept hawthorn and strawberries. Red currants and raspberries exhibited optimal preservation of antioxidant capacity, while hawthorn showed a decrease in the antioxidant capacity during different time points in storage as well as at the end of storage. Analyzed fruits were classified into four main groups based on hierarchical cluster analysis.     

The influence of Ce-based coatings as pretreatments on corrosion stability of top powder polyester coating on AA6060

Cerium-based conversion coatings (CeCCs) are one of the most prospective alternatives to the widely used chromate conversion coatings (CCCs) due to their anticorrosion efficiency, environmentally friendly nature and low cost. In this work, the CeCCs on AA6060 were prepared by immersion into aqueous cerium salt solutions at room temperature, and subsequently post-treated in heated phosphate solution. The effect of counter ion (nitrate and chloride) on the coating properties was studied testing CeCCs as sole or conversion layers for the top polyester coating. Since the 60 μm thick polyester coating was applied, an artificial defect of 0.8 mm hole was introduced to faster assess the differences between pretreatments. The system with CCC pretreatment was used as reference. Corrosion properties were investigated in 0.5 M NaCl solution by electrochemical impedance spectroscopy while the adhesion strength was measured by NMPR (N-methyl-2-pyrrolidone) and pull-off tests. As shown, the post-treated chloride-based CeCC offered better protection than crack-free thin nitrate-based CeCC, when used as sole coatings. On the other hand, it was brought to evidence that in combination with top powder polyester coating, the CeCC deposited from nitrate solution exhibited better protection compared to protective system pretreated with chloride-based one. Excellent polyester coating adhesion was found independently on aluminium surface pretreatment.     

THERMAL ANALYSIS OF LARGE OIL-IMMERSED TRANSFORMER WINDINGS

ABSTRACT

A method of numerical thermal analysis of large oil-immersed transformer windings is presented. The analysis consists of two steps: first, the leakage magnetic field is solved in the windings; second, the basic and additional losses distribution is calculated simultaneously with temperature rise distribution in the cross-sections of individual coils allowing for special geometries and cooling conditions of different types of windings. An example of the analysis is given and the values calculated are compared with the results of factory tests.     

An economic model for the appraisal and selection of energy supply system

Economic evaluation of different energy supply systems (district or local heating by natural gas) in Serbia is considered in this paper. According to variety of Serbian settlements (in density, size and layout of buildings) model which has ability to represent their different characteristics is formed. Model is based on identification of smaller urban areas with identical or similar characteristics and their representations with one of predefined nominal urban areas. For various nominal urban areas preferred type of energy supply system was selected. Obtained results formed matrix of preferred type of energy supply system (district or local heating) for different urban structures. This models’ matrix could be simple and useful tool for initial decision about energy supply system.     

Experimental investigation and thermodynamic prediction of the Bi–Sb–Zn phase diagram

Phase diagram of the ternary Bi–Sb–Zn system was investigated experimentally by DTA and SEM-EDS methods and analytically by CALPHAD method. The liquidus projection, invariant equilibria, several vertical sections and isothermal section at 300 °C were predicted using COST 531 thermodynamic database. Phase transition temperatures of alloys along three predicted vertical sections of the Bi–Sb–Zn ternary system with molar ratio Bi:Sb = 1, Bi:Zn = 1 and Sb:Zn = 1, were measured by differential thermal analysis (DTA). Predicted isothermal section at 300 °C was compared with the results of the scanning electron microscope (SEM) with energy dispersive spectrometry (EDS) analysis from this work.     

Correction of a Piezoresistive Pressure Sensor Using a Microcontroller

A smart piezoresistive pressure sensor using a microcontroller is described. The microcontroller ensures temperature compensation and linearization of the sensor, as well as the data exchange. To compensate for the sensor's imperfection, approximation of the sensor inverse response function by a second-order polynomial in terms of pressure and temperature is used. The maximum measurement error with respect to the full measurement range lies within ±0.1% compared to the ideal sensor response function within the temperature range of 0–70°C.