Changes of Total Tocopherol and Tocopherol Species During Sunflower Oil Processing

The changes of total and individual tocopherols were investigated during different sunflower oil processing stages by reverse-phase high-performance liquid chromatography. The results revealed that the levels of total and individual tocopherol content were decreased during the neutralization, bleaching, and deodorization processes. The overall loss of total tocopherols during these stages was found to be 37.9%, although the general reduction trend of delta (δ), gamma (γ), and alpha (α) tocopherols is very similar during neutralization (35.3%), bleaching (38.3%), and deodorization (37.8%). However, in contrast to the neutralizing and deodorizing stages, the bleaching process caused relatively less reduction for individual tocopherol contents. Deodorizer distillates were also analyzed and were found to be rich with tocopherols content (29,348.24 μg/ml). The results of the study indicated that most parts of the tocopherols are wasted during processing. Therefore, the proper concentration of nutritionists, industrialists, and manufacturers is needed for the necessary improvements in processing technology to avoid the major loss of tocopherols and to increase the shelf life, as well as the nutritive value of processed oil.     

Effect of blending ratio and catalyst loading on co-gasification of wood chips and coconut waste

Catalytic co-gasification is an important tar reforming technique, which may appreciably improve the quality of syngas through tar reforming reaction. In this study, wood chips (WC) were co-gasified with two coconut wastes, namely coconut shells (CS) and coconut fronds (CF), in a downdraft gasifier. The dolomite and limestone were used as tar reforming mediums. The effect of the blending ratio, catalyst type, biomass type and catalyst to biomass loading on gas composition and heating value of the syngas was investigated for different WC/CS and WC/CF blends. The results revealed that the WC/CS blending ratio of 70:30 produces the highest H₂ amount (11.70 vol.%), which was 31% higher than the H₂ amount of the other blends. The HHV_syngas of 70:30 blend was measured about 4.96 MJ/Nm³, which was also higher among all the tested blends. The co-gasification of 70:30 blend of WC/CS, when compared with same blending ratio WC/CF, produced two times higher CO, 60% higher H₂ and 75% higher HHV_syngas. During catalytic co-gasification of WC/CS blends with dolomite and limestone, the dolomite yielded 24%, 13.8% and 25.6% increment in CO, H₂, and CH₄, respectively. It is concluded that the coconut wastes can be substituted or co-gasified with wood after carrying out some major changes in a gasifier geometry.     

Analysis of the essential work of fracture method as applied to UHMWPE

The validity of the basic assumptions behind the method of essential work of fracture (EWF), as applied to ultra-high molecular weight polyethylene (UHMWPE), is evaluated using finite element modelling. To define a suitable model of constitutive behaviour, the mechanical properties of UHMWPE have been measured in both uniaxial tension and compression over a range of strain rates. The observed strain rate dependence of stress, including the observed differences in strain rate sensitivity between tension and compression, is interpreted in terms of a single Eyring process. The constitutive theory is constructed comprising an Eyring process and hyperelastic networks, the latter having responses symmetric with respect to tension and compression. This theory is implemented within a finite element scheme, and used to model fracture measurements made on the same material using double-edge notch tensile specimens. Calculations of the non-essential work and of the extent of the plastic zones are thus made possible. It is concluded that the specific non-essential work is essentially constant, but that the shape factor β, assumed constant in the conventional analysis, varies significantly with ligament length. The implication of this finding on the derived EWF value is evaluated and found to be slight.     

Nonlinear Decentralized Feedback Linearizing Controller Design for Islanded DC Microgrids

This paper aims to design decentralized controllers for different components in islanded DC microgrids. The major components in the DC microgrid as considered in this paper include a fuel cell, solar photovoltaic (PV) unit, and battery energy storage system (BESS) along with critical and non-critical loads. The main control objective is to maintain the power balance within the DC microgrid through the regulation of the common DC-bus voltage. The controllers are designed based on the dynamical models of the fuel cell, solar PV unit, and BESS. The feedback linearization technique is employed to obtain the control laws, which simplifies the original dynamical models and decouples different components in the form of several subsystems. In this way, the feedback linearization technique allows different components in DC microgrids to achieve the desired control objectives by using only the local information (i.e., in a decentralized manner). The performance of the proposed decentralized controllers for different components is evaluated on a test DC microgrid under different operating conditions. Simulation results demonstrate that the proposed control scheme performs in a much better way as compared to an existing proportional integral controller.     

Structure and mechanical properties of blends of poly(ε‐caprolactone) with a poly(amino ether)

Poly(ε‐caprolactone) (PCL)/poly(amino ether) (PAE) blends were obtained by injection molding without any previous extrusion step in an attempt to (i) contribute to the knowledge of the relation between structure and mechanical properties in these type of blends composed of a rubbery and a glassy polymer and (ii) to find out to which extent are the PCL/PAE blends compatible, and therefore whether the biodegradability of PCL can be added as a characteristic of PAE‐based applications. PCL/PAE blends are composed of a crystalline PCL phase, a pure amorphous PCL phase, and a PAE‐rich phase where some PCL is present. The presence of some dissolved and probably unreacted PCL in the PAE‐rich phase led to a low interfacial tension as observed by the small size of the dispersed particles and the large interfacial area. The dependence on composition of both the modulus of elasticity and the yield stress of the blends was parallel to that of the orientation level. The elongation at break showed values similar to those of PAE in PAE‐rich blends, and was slightly synergistic in very rich PCL compositions; this behavior reflects a change in the nature of the matrix, from glassy to rubbery. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Performance of a Cocoa Butter-Like Fat Enzymatically Produced from Olive Pomace Oil as a Partial Cocoa Butter Replacer

Olive pomace oil is a by-product of olive oil processing and it is considered a low-quality oil. Considering its suitable triacylglycerol (TAG) composition, this work aimed to convert refined olive pomace oil (ROPO) to a cocoa butter (CB)-like fat using sn-1,3 specific lipase, and to investigate its performance as a partial CB replacer. CB-like fat was produced from olive pomace oil by sn-1,3-specific lipase-catalyzed acidolysis in a packed bed reactor. Binary blends of CB and CB-like fat (CB:CB-like fat) were prepared in different proportions, and their physicochemical characteristics [TAG content, melting profile, solid fat content (SFC) and microstructure] were investigated. The contents of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), 1(3)-palmitoyl-3(1)stearoyl-2-oleoyl-glycerol (POS) and 1,3-distearoyl-2-oleoyl-glycerol (SOS) in the 100:0 blend were 18.9, 33.1 and 24.7%, respectively. These contents decreased to 11.0, 20.0 and 11.7%, respectively, in the 0:100 blend. Although the melting point (28.5 °C) did not change significantly above 30% CB-like fat addition, the shape of the melting peak became wider and irregular. An isothermal solid diagram of SFC showed that better compatibility was observed at temperatures above 35 °C for all blends. Addition of over 30% CB-like fat caused significant difference in the microstructure.