Lipid shortenings: a review

A critical introduction to lipid shortening systems is provided. The review covers types, formulations, functionality, and processing conditions required for the production of lipid shortening systems. Furthermore, lipid shortenings and their production are placed within the context of recent advances in the areas of crystallization, structural elucidation, and mechanical modeling of fat crystal networks in general. The various unit operations involved in the production of lipid shortenings are examined in light of the evolution of structure (both at the crystalline and microstructural levels) and derived physical functionality.     

Organic acids catalyzed polymerization of ε‐caprolactone: Synthesis and characterization

Environmentally friendly organocatalytic synthesis of aliphatic polyesters was studied. The catalysis investigated is novel, and lends itself well to the potential production of valuable biodegradable products. The reactions were based on an organic acids‐catalyzed ring‐opening polymerization of ε‐caprolactone with fatty acid derivatives as the initiator and were performed in the absence of solvents. The chemical structures of the functionalized polymers were confirmed by ¹H and ¹³C‐NMR spectra. Polymers with different molecular weights, in the range 10,900–15,200 were obtained in the presence of fumaric acid as catalyst. The thermal properties of the functionalized PCLs were determined by modulated differential scanning calorimetry and thermogravimetric analysis. The MDSC results verified that the crystallinity and the melting point of the lipid‐functionalized polymers were lower than that of the unfunctionalized poly(ε‐caprolactone). The hydrolytic degradation of the functionalized polymer was also investigated. The result shows the degradation rate was affected by the presence of oleic acid derivatives in the polymer molecule. The lipid‐functionalized polymers synthesized by the metal‐free polymerization systems seem to be suitable biodegradable polyesters for use in biomedical and pharmacological applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study of the polarizations of (Al,Ga,AlGa)N nitride compounds and the charge density of various interfaces based on them

The results of a theoretical study based on ab initio calculations of the polarization properties of AlN, GaN, and AlGaN semiconductors with the wurtzite structure are presented. The values of the spontaneous and piezoelectric polarizations, as well as the piezoelectric constants, are calculated for these nitride compounds. With the aim of further considering prospective heterostructures based on (Al,Ga,AlGa)N compounds, the charge densities at the AlN/GaN, AlGaN/AlN, and AlGaN/GaN interfaces and carrier concentration at the AlGaN/GaN heterointerface is estimated and compared with the experimental data.     

Inverse-Coefficient Problem of Heat Transfer in Layered Nanostructures

Russian Microelectronics - The rapid development of electronics is leading to the creation and use of small electronic components, including nanoelements of a complex layered structure. The search...     

Issues of Implementing Neural Network Algorithms on Memristor Crossbars

Russian Microelectronics - The property of the natural parallelization of matrix-vector operations inherent in memristor crossbars creates opportunities for their effective use in neural network...     

Multi-length-Scale Elucidation of Kinetic and Symmetry Effects on the Behavior of Stearic and Oleic TAG. I. SOS and SSO

Positional isomerism in triacylglycerols (TAG), present in a molecular ensemble arising from genetic, environmental or processing-induced changes, can result in significant differences in the macroscopic physico-chemical functionality of crystallized networks of the ensemble. The differences in phase behavior induced by positional isomerism and levels of unsaturation of pure oleoyl-distearoyl TAG (SOS, SSO) were detailed at different length scales. The effect of cooling rate on the polymorphism, thermal properties and microstructure were systematically investigated between 0.1 and 5 °C/min. The symmetrical SOS presented a complex polymorphism and microstructure, which varied predictively with cooling rate. The crystal phases and transitions observed for this TAG are similar to those of cocoa butter. In contrast, the cooling rate had limited effect on the phase behavior of the asymmetrical SSO. The differences between the crystallization of SSO and SOS induced by kinetics are related to the kinked oleic acid at the outer position in the SSO molecule and favorable end group structure for SOS. The fundamental understanding gained from such model systems can be used in many industrial formulations, particularly foods.     

Multi-Length-Scale Elucidation of Kinetic and Symmetry Effects on the Behavior of Stearic and Oleic TAG. II: OSO and SOO

The phase composition of triacylglycerols (TAG) is determined by chemical structure and is greatly affected by kinetics. Positional isomerism and unsaturation are two key structural elements that govern, for a large part, the phase behavior of TAG during crystallization. Polymorphism, thermal properties, and microstructure of dioleoyl‐stearoyl isomers (OSO, SOO) were investigated at different cooling rates with XRD, DSC and PLM techniques, respectively. The physical properties of the symmetrical TAG were found to predictably vary with cooling rate; whereas, the properties of the asymmetrical TAG remained relatively constant. This was explained to be mainly due to the extra steric hindrance caused by asymmetry and the disturbances introduced at the “terrace” level via methyl‐end group interactions. The findings underscore the intricate contribution of saturation and symmetry to the phase trajectories of diunsaturated TAG. The knowledge gained will help understand the behavior of more complex materials and can be used for the manipulation of fat structures at different length scales and direct the manufacture of novel food systems and other relevant materials.     

Polyurethanes from benzene polyols synthesized from vegetable oils: Dependence of physical properties on structure

Asymmetric and symmetric aromatic triol isomers were synthesized from erucic acid. The pure asymmetric and symmetric triols were crosslinked with MDI into their corresponding polyurethane sheets. The physico‐chemical properties of these polyurethanes were studied by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis coupled with Fourier transform infrared (TGA‐FTIR) spectroscopy, and tensile analysis. The A‐PU and S‐PU demonstrated differences in their glass transition temperatures (T_g) and crosslinking densities. The difference in T_g of these polyurethanes could be explained by the differences in crosslinking densities, which could be related to the increase in steric hindrance, to the crosslinking MDI molecules, between adjacent hydroxyl groups of the asymmetric triol monomers. Overall, it was found that both polyurethanes had similar mechanical and thermal properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Investigating business-IT alignment through multi-disciplinary goal concepts

The alignment of information technology (IT) with business strategies is optimal when harmony exists between organizational and system goals. Empirical evidence reveals that effective strategic alignment leads to superior financial performance for organizations. This observation has spurred extensive research into business-IT alignment. Yet, the issue of alignment remains a top concern for CIOs. We argue that the parochial view undertaken by past research into business-IT alignment is a probable cause for continuing system failures. Furthermore, strategic alignment research is limited and devoid within the requirements engineering discipline. In this paper, we highlight existing shortfalls of research in business-IT alignment, and bring to light insights that may be offered by other disciplines to augment this field. Subscribing to a multi-disciplinary perspective, we develop a goal-based framework that incorporates goals from various literatures in investigating business-IT alignment. One of the novelties of our proposed framework lies in its delineation between goals that have been originally assigned to stakeholders versus those interpreted by stakeholders. Additionally, the framework includes constructs at the strategic level for supporting the rationale of strategic level goals. We tested the usefulness and usability of this methodology in an organization with a newly developed information system founded on strategic business goals and reported lessons learnt from both researchers’ and practitioners’ perspectives.