Adsorption isotherms of sesame oil in a concentrated miscella system

The adsorption of peroxides, unsaturated carbonyls, free fatty acids and carotenoids from unrefined sesame oil on vegetable carbon (5%, w/w) in a miscella system was studied. Three different solvent conditions (hexane/ethanol, 100:0, 95:5 and 75:25, vol/vol), combined in a factorial design with five levels of solvent (0, 10, 20, 30 and 40%, w/w), were used to develop the miscella. Equilibrium adsorption was not achieved during the 100 min of adsorption, mainly because the oil components were involved in oxidation reactions during the adsorption process. However, for a given solvent concentration, adsorption of the oil components showed a significant linear regression on their respective initial concentration in the miscella (C_i). Peroxides and carbonyls showed, at all solvent levels investigated, an affinity for the carbon more independent of their C_i than free fatty acids and carotenoids. In general, at the same C_i, a higher adsorption was achieved as solvent concentration increased. The results indicated that free fatty acid adsorption may depend on competitive adsorption based on molecule hydrophobicity. However, in spite of the higher hydrophobicity of carotenoids, compared with free fatty acids, they might not be competing for the same adsorbing sites. Ethanol showed a prooxidant effect that increased peroxide production during adsorption but did not affect the reaction involved in carbonyl production.     

Effect of DAG on milk fat TAG crystallization

The effect of milk fat and standard DAG on the crystallization behavior of milk fat TAG (MF-TAG) was investigated. When milk fat DAG were added to MF-TAG at the 0.1 wt% level, crystallization was delayed. Racemic purity was shown to be an important factor in the ability of DAG to influence TAG crystallization. Only sn-1,2 isomers of blends of MF-TAG with 0.1 wt% of the racemic mixtures of dipalmitin and diolein increased the activation free energy barrier to MF-TAG nucleation (ΔG _c ) and delayed the subsequent crystallization process by increasing the crystallization induction time (τ_SFC) determined from solid fat content-time measurements. Although crystallization kinetics were affected, the properties of the resulting network structures remained unchanged upon addition of milk fat minor components at the 0.1 wt% level     

Optimal linear filter design for systems with correlation in the measurement matrices and noises: recursive algorithm and applications

This paper addresses the optimal least-squares linear estimation problem for a class of discrete-time stochastic systems with random parameter matrices and correlated additive noises. The system presents the following main features: (1) one-step correlated and cross-correlated random parameter matrices in the observation equation are assumed; (2) the process and measurement noises are one-step autocorrelated and two-step cross-correlated. Using an innovation approach and these correlation assumptions, a recursive algorithm with a simple computational procedure is derived for the optimal linear filter. As a significant application of the proposed results, the optimal recursive filtering problem in multi-sensor systems with missing measurements and random delays can be addressed. Numerical simulation examples are used to demonstrate the feasibility of the proposed filtering algorithm, which is also compared with other filters that have been proposed.     

Beast methodology: An agile testing methodology for multi-agent systems based on behaviour driven development

This paper presents a testing methodology to apply Behaviour Driven Development (BDD) techniques while developing Multi-Agent Systems (MASs), termed BEhavioural Agent Simple Testing (BEAST) Methodology. This methodology is supported by the open source framework (BEAST Tool) which automatically generates test cases skeletons from BDD scenarios specifications. The developed framework allows the testing of MASs based on JADE or JADEX platforms. In addition, this framework offers a set of configurable Mock Agents with the aim of being able to execute tests while the MAS is under development. The BEAST Methodology presents transparent traceability from user requirements to test cases. Thus, the stakeholders can be aware of the project status. The methodology and the associated tool have been validated in the development of a MAS for fault diagnosis in FTTH (Fiber To The Home) networks. The results have been measured in quantifiable way obtaining a reduction of the tests implementation time.     

Fast training procedure for Viola–Jones type object detectors using Laplacian clutter models

This paper presents a fast training strategy for the Viola–Jones (VJ) type object-detection systems. The VJ object- detection system, popular for its high accuracy at real-time testing speeds, has a drawback that it is slow to train. A face detector, for example, can take days to train. In content-based image retrieval (CBIR), where search needs to be performed instantaneously, VJ’s long training time is not affordable. Therefore, VJ’s method is hardly used for such applications. This paper proposes two modifications to the training algorithm of VJ-type object detection systems which reduces the training time to the order of seconds. Firstly, Laplacian clutter (non-object) models are used to train the weak classifier, thus eliminating the need to read and evaluate thousands of clutter images. Secondly, the training procedure is simplified by removing the time-consuming AdaBoost-based feature selection procedure. An object detector, trained with 500 images, approximately takes 2 s for training in a conventional 3 GHz machine. Our results show that the accuracy of the detector, built with the proposed approach, is inferior to that of VJ for difficult object class such as frontal faces. However, for objects with lesser degree of intra-class variations such as hearts, state-of-the-art accuracy can be obtained. Importantly, for CBIR applications, the fast testing speed of the VJ type object detector is maintained.     

Morphology and thermomechanical properties of recycled PET–organoclay nanocomposites

Recycled PET/organoclay nanocomposites were prepared by melt intercalation process with several amounts (1, 3, and 5 wt %) of clay modified with quaternary ammonium salt (DELLITE 67G) dispersed in a recycled poly(ethylene terephthalate) (rPET) matrix. The resultant mechanical properties (modulus and yield strength) of the nanocomposites were found to be different from those of rPET. Wide angle X‐ray scattering (WAXS) and Transmission Electron Microscopy (TEM) measurements have shown that although complete exfoliation was not achieved, delaminated clay platelets could be observed. Thermal analysis did not show significant changes in the thermal properties from those of recycled PET. Mechanical testing showed that nanocomposite properties were superior to the recycled PET in terms of strength and elasticity modulus. This improvement was attributed to nanoscale effects and strong interaction between the rPET matrix and the clay interface, as revealed by WAXS and TEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1839–1844, 2007     

Random Copolymers with 2,2′-Dioxy-1,1′-biphenyl-phosphazene and Chiral 2,2′-dioxy-1,1′-binaphthylphosphazene Units Functionalized in the 6,6′-Positions with PPh<Subscript>2</Subscript> Groups as Precursors for Ru(arene) Catalysts

The chiral phosphazene copolymers {[NP(O₂C₁₂H₈)]_0.9[NP(O₂C₂₀H₁₂)]_0.1} (1) and {[NP(O₂C₁₂H₈)]_0.9[NP(O₂C₂₀H₁₀Br₂)]_0.1} _n (2) [(O₂C₁₂H₈) = 2,2′-dioxy-1,1′-biphenyl; (O₂C₂₀H₁₂) = R-2,2′-dioxy-1,1′-binaphthyl and (O₂C₂₀H₁₀Br₂) = R-6,6′-dibromo-2,2′-dioxy-1,1′-binaphthyl] were prepared by sequential substitution from [NPCl₂] _n and the corresponding dihydroxy-biphenyl or binaphthyl reagents in the presence of Cs₂CO₃ and K₂CO₃. The reaction of (2) with ^tBuLi in THF, followed by addition of PPh₂Cl and a treatment with SiHCl₃/PPh₃ to eliminate any oxidized OC₆H₄P(O)Ph₂ groups, gave the phosphine containing copolymer {[NP(O₂C₁₂H₈)]_0.9[NP(O₂C₂₀H₁₀[PPh₂]₂)]_0.1} _n (3), that was used as a chiral ligand to support [Ru(p-cymene)Cl] complexes. The resulting catalyst was active for hydrogen transfer from isopropyl alcohol to acetophenone but the placement of the Ru centers in the 6,6′-positions of the binaphthoxyphosphazene units induced no enantioselectivity. Dedicated to Professor Christopher Allen.     

Restructuring butterfat through blending and chemical interesterification. 3. Rheology

Interesterified and noninteresterified butterfat-canola oil blends, ranging from 100% butterfat to 60∶40 butterfat-canola oil (w/w) in 10% increments, were evaluated for hardness index (HI), dropping point, viscosity, and viscoelastic properties at small deformation. Both blending and chemical interesterification diminished HI in a nonlinear fashion. HI changes in interesterified blends were more pronounced than in noninteresterified blends. Dropping points yielded information on the structure of the blends. Butterfat’s dropping point (DP) was 34.4°C, whereas that of interesterified butterfat was 37.0°C, which is indicative of a more structured network for the latter. DP values of blends with 60–90% butterfat (interesterified vs. noninteresterified) were not significantly different (P<0.05). Interesterified blends had a higher crystallization onset temperature than did noninteresterified blends. All blends in the liquid state displayed Newtonian behavior. Oscillatory frequency sweep measurements at small amplitude showed that interesterified blends generally had lower storage moduli (G′) than their noninteresterified counterparts. BothG′ andG″ were frequency-dependent. Replacement of 30% butterfat by canola oil led to notable changes in small deformation measurements, whereas replacement of 20% butterfat led to big changes in large deformation measurements.     

<Emphasis Type="Italic">In situ</Emphasis> monitoring of solid fat content by means of pulsed nuclear magnetic resonance spectrometry and ultrasonics

An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships were found between ultrasonic parameters [integrated response, time of flight (TF), and full width half maximum] and SFC. TF, which is an indirect measurement of the ultrasonic velocity (v), was highly correlated to SFC (r ²>0.9) in a linear fashion (v=2.601 SFC+1433.0).     

Protection of stainless steel by polyaniline films against corrosion in aqueous environments

Polyaniline (PANI) thin films were electrochemically deposited by cyclic voltammetry on stainless steel electrode previously covered by a thin film of polyvinyl acetate (PVAc). The corrosion resistance of PANI covered stainless steel substrates was estimated by using potentiodynamic polarization curves and its linear polarization resistance (LPR) was measured in 0.5 M H₂SO₄, 0.5 M NaCl and 0.5 M NaOH aqueous solutions at room temperature. The results indicate that the PANI-PVAc films did improve the corrosion resistance of the stainless steel in NaOH, behaving even worst, in the case of PANI film, than the uncoated substrate. In H₂SO₄ both PANI and PANI-PVAc coatings gave good protection for the stainless steel electrode, with a slightly better performance of PANI-PVAc than PANI. In NaCl solution both PANI and PANI-PVAc films provided a good protection against corrosion. The better performance of PANI-PVAc coatings for corrosion protection in basic media may be due to its major chemical stability compared to simple PANI films, which lose their conductivity in high pH solutions. The E _corr (free corrosion potential) value of the coated substrate was in the passive region of the uncoated substrate in acidic environment but in the active region in neutral or basic environment.