Effect of thermal pre-treatment on the phenolic and protein profiles and oil oxidation dynamics of golden flaxseeds

The food industry is interested in the application of thermally pre-treated flaxseeds because the treatment improves their sensory acceptability and reduces anti-nutrient contents. However, it may influence the health benefits of flaxseed compounds. The changes in the phenolic and protein profiles, and in situ oil oxidation dynamics after steaming or roasting of flaxseeds were analysed to study this effect. The results showed that the pre-treatment of flaxseeds did not affect the content of major flaxseed phenolics. Steaming and roasting considerably changed the flaxseed protein profile. The thermally induced protein aggregation and/or cross-linking occurred. The most significant changes were found for the 13 and 53 kDa proteins. Flaxseed roasting deteriorated the oil oxidative stability significantly more than steaming. These changes may decrease the nutritional quality and shelf life of roasted or steamed flaxseeds. They should be monitored when pre-treated flaxseeds are intended to be used as a food ingredient.     

Novel clustering-based pruning algorithms

Pattern Analysis and Applications - One of the crucial problems of designing a classifier ensemble is the proper choice of the base classifier line-up. Basically, such an ensemble is formed on the...     

Effect of surface treatment on the properties of polypropylene/nanoboehmite composites

Boehmite nanoparticles are surface modified with alkyl phosphorous acid to improve their dispersion in polypropylene. Effective grafting is evidenced by NMR, elemental analysis and by the fact that the dispersion ability (or disagglomeration) of grafted boehmite particle in nonpolar solvent is significantly altered. High dispersibility level in PP is obtained with long alkyl chain surface modifiers. The improvement of the nanocomposites thermal stability is correlated with the nanoparticles dispersion level. However, composite with well dispersed nanoparticle did not demonstrate enhanced mechanical properties because of weak polymer/filler interactions with the PP matrix. Better reinforcement is noticed for polypropylene composite loaded with untreated boehmite or treated with shorter alkyl chain. For these composites, the nanoparticles acted as nucleating agents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Analysis of Possibilities of Application of Nanofabricated Thermal Probes to Quantitative Thermal Measurements

A steady-state thermal model of the nanofabricated thermal probe was proposed. The resistive type probe working in the active mode was considered. The model is based on finite element analysis of the temperature field in the probe-sample system. Determination of the temperature distribution in this system allows calculations of relative changes in the probe electrical resistance. It is shown that the modeled probe can be used for measurements of the local thermal conductivity with the spatial resolution determined by the probe apex dimensions. The probe exhibits the maximum sensitivity to the changes in the thermal conductivity of the sample between 2 W·m⁻¹ ·K⁻¹ and 200 W·m⁻¹ ·K⁻¹. The influence of the thermal conductivity of the probe substrate on metrological characteristics of the probe as well as the thermal resistance of the probe-sample contact on the determination of the sample thermal conductivity were also analyzed. The selected results of numerical analysis were compared with data of preliminary experiments.     

Microstructure,chemical composition,wear, and corrosion resistance of FeB–Fe<Subscript>2</Subscript>B–Fe<Subscript>3</Subscript>B surface layers produced on Vanadis-6 steel using CO<Subscript>2</Subscript> laser

The paper presents the study results of laser modification of FeB–Fe₂B surface layers produced on Vanadis-6 steel using pack cementation method. Microstructure, x-ray phase analysis, chemical composition study using wave dispersive spectrometry method, microhardness, corrosion resistance as well as surface condition, roughness, and wear resistance were investigated. The diffusion boronizing processes were performed at 900 °C for 5 h in the EKabor® powder mixture. The boronized layers had a dual-phase microstructure composed of two types of iron borides, FeB and Fe₂B, and their microhardness ranged from 1800 to 1400 HV. The laser surface modification was carried out on specimens after diffusion boronizing process using CO₂ laser with a nominal power of 2600 W. Laser beam power used in this experiment was equal to 1040 W and was constant. While the three values of scanning speed were used: 19, 48, and 75 mm/s. During laser modification, the multiple tracks were made where distance between of axis tracks was equal to 0.5 mm. As a result of this process, microstructure consisted of remelted zone, heat-affected zone, and substrate was obtained. In remelted zone, the boron-martensite eutectic was observed. Boronized layers after laser modification were characterized by the mild gradient of microhardness from surface to the substrate and their value was dependent on the scanning speed used and was between 1700 and 1100 HV. Corrosion resistance tests revealed reducing the current of corrosion in case of laser modification process. Wear resistance of laser modified specimens was improved in comparison to diffusion boronized layers.     

Quantitative surface acoustic wave detection based on colloidal gold nanoparticles and their bioconjugates

The immobilization scheme of monodispersed gold nanoparticles (10-nm diameter) on piezoelectric substrate surfaces using organosilane molecules as cross-linkers has been developed for lithium niobate (LiNbO3) and silicon oxide (SiO2)/gold-covered lithium tantalate (LiTaO3) of Rayleigh and guided shear horizontal- (guided SH) surface acoustic wave (SAW) sensors. In this study, comparative measurements of gold nanoparticle adsorption kinetics using high-resolution field-emission scanning electron microscopy and SAW sensors allow the frequency responses of SAW sensors to be quantitatively correlated with surface densities of adsorbed nanoparticles. Using this approach, gold nanoparticles are used as the "nanosized mass standards" to scale the mass loading in a wide dynamical range. Rayleigh-SAW and guided SH-SAW sensors are employed here to monitor the surface mass changes on the device surfaces in gas and liquid phases, respectively. The mass sensitivity ( approximately 20 Hz.cm2/ng) of Rayleigh-SAW device (fundamental oscillation frequency of 113.3 MHz in air) is more than 2 orders of magnitude higher than that of conventional 9-MHz quartz crystal microbalance sensors. Furthermore, in situ (aqueous solutions), real-time measurements of adsorption kinetics for both citrate-stabilized gold nanoparticles and DNA-gold nanoparticle conjugates are also demonstrated by guided SH-SAW (fundamental oscillation frequency of 121.3 MHz). By comparing frequency shifts between the adsorption cases of gold nanoparticles and DNA-gold nanoparticle conjugates, the average number of bound oligonucleotides per gold nanoparticle can also be determined. The high mass sensitivity ( approximately 6 Hz.cm2/ng) of guided SH-SAW sensors and successful detection of DNA-gold nanoparticle conjugates paves the way for real-time biosensing in liquids using nanoparticle-enhanced SAW devices.     

Fire performance and mechanical properties of acrylonitrile‐butadiene‐styrene copolymer/modified expandable graphite composites

The fire performance and mechanical properties of an acrylonitrile‐butadiene‐styrene (ABS) copolymer compounded with different expandable graphites (EG) and fire retardants were studied by using the limiting oxygen index test, the UL‐94 test, a mechanical test, and a thermogravimetric analysis. The ground EG treated with phosphoric acid and silane could have the great increase of the volume expansion ratio. The addition of the treated EG in ABS significantly enhances the fire performance but decreases the impact strength of ABS. ABS with the treated EG has a much higher impact strength than with the as‐received EG because of the smaller particle size of the treated EG and the better adhesion between the ABS and the treated EG. The addition of modified ammonium polyphosphate or decabromodiphenyl oxide/antimony trioxide can considerably improve the fire performance of ABS/treated EG composites because of a synergistic effect. The V‐0 grade (UL‐94) ABS composite with the limiting oxygen index of 32.5 can be obtained by adding small amounts of the treated EG and modified ammonium polyphosphate into ABS. Thermogravimetric analysis results indicate that the initial vapor release temperatures and the weight loss rates of ABS/EG composites are closely related to their fire performance and affected by the fire retardant used. Copyright © 2011 John Wiley & Sons, Ltd.