RETRACTED ARTICLE: Investigation of Frying Oil Quality Using VIS/NIR Hyperspectral Analysis

Traditional chemical methods of analyzing frying oil quality are time-consuming and not amenable to on-line measurement. The main objective of this study was to evaluate quality changes of heated oils based on visible/near infrared spectral analysis using a hyperspectroradiometer. The reflectance spectra of the heated oils were analyzed within the range 400–1,750 nm. Acid value, total polar component, and viscosity of oil samples were used as indicators of different quality levels of oil. Partial least squares calibration models were developed for quantitative evaluations of these parameters. The R ² and root mean square error for each prediction were calculated to assess the prediction capability of calibration models. The study demonstrated that using the established calibration models, quality parameters could be predicted with R ² values over 0.92.     

Combined influences of viscous dissipation,non-uniform Joule heating and variable thermophysical properties on convective heat transfer in microtubes

This study presents a comprehensive investigation on hydrodynamic and thermal transport properties of mixed electroosmotically and pressure driven flow in microtubes. Particular emphasis is given to investigating the combined consequences of viscous dissipation, non-uniform Joule heating, and variable thermophysical properties. Analytical solutions are obtained using the Debye–Hückel linearization and constant fluid properties assumption, while a numerical solution is presented for variable fluid properties and non-uniform distribution of Joule heating. The results indicate that, viscous heating effect is pronounced significantly when a favorable pressure gradient exists and cannot be neglected at low values of the dimensionless Debye–Hückel parameter. Moreover, uniform Joule heating assumption, even at low zeta potentials, may reduce the accuracy of the predicted thermal features considerably. The wall shear stress is found to be strongly dependent upon the zeta potential, which is underestimated by the Debye–Hückel linearization. Compared with the constant fluid properties case, decreasing electrical resistivity of the fluid by increasing temperature, amplifies the total energy generation due to the Joule heating and reduces the Nusselt number.     

Wetting transparency of graphene

We report that graphene coatings do not significantly disrupt the intrinsic wetting behaviour of surfaces for which surface-water interactions are dominated by van?der?Waals forces. Our contact angle measurements indicate that a graphene monolayer is wetting-transparent to copper, gold or silicon, but not glass, for which the wettability is dominated by short-range chemical bonding. With increasing number of graphene layers, the contact angle of water on copper gradually transitions towards the bulk graphite value, which is reached for ~6 graphene layers. Molecular dynamics simulations and theoretical predictions confirm our measurements and indicate that graphene's wetting transparency is related to its extreme thinness. We also show a 30-40% increase in condensation heat transfer on copper, as a result of the ability of the graphene coating to suppress copper oxidation without disrupting the intrinsic wettability of the surface. Such an ability to independently tune the properties of surfaces without disrupting their wetting response could have important implications in the design of conducting, conformal and impermeable surface coatings.     

FTIR and thermal analyses of intermolecular interactions in poly(trimethylene terephthalate)/phenoxy blends

Intermolecular interactions in the blends of poly(trimethylene terephthalate)/phenoxy resin of bisphenol A prepared by melt mixing in a microcompounder were studied using Fourier transform infrared (FTIR) spectroscopy and thermal analysis. The FTIR results revealed the characteristic bands of the blend constituents along with the bands showing interassociated, self‐associated, and nonassociated hydrogen bonding in the blends. It was found that the self‐associated hydrogen bonds in the blends were favorable over the interassociated bonds. On the other hand, using the melting point depression, the interaction parameter of the blends was calculated to be about 0.047. The positive value of the interaction parameter and low degree of interassociated hydrogen bonding in the blends suggest the immiscibility of the blends, which is confirmed by scanning electron microscopy observations as well as dynamic mechanical analysis. However, for chemically reacted compositions, the blends were changed to homogenous systems. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Crystallization of Ti33Cu67 metallic glass under high-current density electrical pulses

We have studied the phase and structure evolution of the Ti₃₃Cu₆₇ amorphous alloy subjected to electrical pulses of high current density. By varying the pulse parameters, different stages of crystallization could be observed in the samples. Partial polymorphic nanocrystallization resulting in the formation of 5- to 8-nm crystallites of the TiCu₂ intermetallic in the residual amorphous matrix occurred when the maximum current density reached 9.7·10⁸ A m^-2 and the pulse duration was 140 μs, though the calculated temperature increase due to Joule heating was not enough to reach the crystallization temperature of the alloy. Samples subjected to higher current densities and higher values of the evolved Joule heat per unit mass fully crystallized and contained the Ti₂Cu₃ and TiCu₃ phases. A common feature of the crystallized ribbons was their non-uniform microstructure with regions that experienced local melting and rapid solidification.PACS: 81; 81.05.Bx; 81.05.Kf.     

An LO architecture with novel wide locking range,quadrature output RILFDs and ILROs for cognitive radio applications

In this paper, a wide locking range, quadrature output ring type injection locked frequency divider (ILFD) is presented for division ratios of 3 and 4. This ILFD proposes a novel injection scheme that shapes the injection signal to a proper form and provides a convenient situation for divider locking. Furthermore, two new wide locking range, low power consumption, injection locked ring oscillators (ILROs) are proposed for quadrature generation in local oscillator architectures. A novel cognitive radio quadrature local oscillator (LO) architecture is presented by utilizing the proposed ILFDs and ILROs to verify the effectiveness of the proposed circuits. Moreover, a new technique is implemented on the LO architecture to widen the frequency range without consuming any extra power. Because of using a single LC tank, this architecture is very compact. Also, it has the benefit of low power consumption and low output phase noise.     

[(Fe<Subscript>0.5</Subscript>Co<Subscript>0.5</Subscript>)<Subscript>0.75</Subscript>B<Subscript>0.20</Subscript>Si<Subscript>0.05</Subscript>]<Subscript>96</Subscript>Nb<Subscript>4</Subscript> Metallic Glasses with Small Cu Additions

Recently, (Fe-Co)-B-Si-Nb bulk metallic glasses (BMGs) were produced. Such BMGs exhibit high glass-forming ability (GFA) as well as good mechanical and magnetic properties. These alloys combine the advantages of functional and structural materials. The soft magnetic properties can be enhanced by nanocrystallization. To force the nanocrystallization, small content of Cu was added to the starting composition. In this article, {[(Fe_0.5Co_0.5)_0.75Si_0.05B_0.20]_0.96Nb_0.04}_100–x Cu _x glassy alloys (x = 1, 2, and 3) were chosen for investigation. The GFA and the thermal stability of these alloys were evaluated. The effects of crystallization during heat-treatment processes on the phase evolution and the magnetic properties, including M _s , H _c , and T _c , in these alloys were investigated. The phase analyses were done with the help of the X-ray diffraction patterns recorded in situ by using the synchrotron radiation in transmission configuration.