Physical properties of normal grade biodiesel and winter grade biodiesel

In this study, optical and thermal properties of normal grade and winter grade palm oil biodiesel were investigated. Surface Plasmon Resonance and Photopyroelectric technique were used to evaluate the samples. The dispersion curve and thermal diffusivity were obtained. Consequently, the variation of refractive index, as a function of wavelength in normal grade biodiesel is faster than winter grade palm oil biodiesel, and the thermal diffusivity of winter grade biodiesel is higher than the thermal diffusivity of normal grade biodiesel. This is attributed to the higher palmitic acid C(16:0) content in normal grade than in winter grade palm oil biodiesel.     

Physical properties of palm‐based diacylglycerol and palm‐based oils in the preparation of shelf‐stable margarine

Ternary mixtures containing palm olein (POL), palm kernel oil (PKO) and palm oil‐based diacylglycerol (PO‐DAG) were designed using mixture design. The corresponding physical properties such as solid fat content (SFC) as well as deviation from SFC (ΔSFC) using nuclear magnetic resonance (NMR) and melting and crystallization properties using differential scanning calorimetry (DSC) were studied. Ternary phase behaviour was analysed using isosolid diagrams. The most intensive eutectic interaction among the three binary blends studied was observed along the binary line of PKO/PO‐DAG followed by POL/PKO and POL/PO‐DAG. The higher ΔSFC did not always lead to the more intensive eutectic behaviour among the blends. Addition of pure POL, 33.33 and 66.66% POL, and no POL to 50/50 mixture of PKO/PO‐DAG decreased heat of crystallization (ΔHc) as well as crystallization onset (T_O). However, as the same amounts of PO‐DAG and PKO were added to the 50/50 mixtures of POL/PKO and POL/PO‐DAG, respectively, blend containing the equi‐mixture of POL, PKO and PO‐DAG (33.33/33.33/33.33) was found to have the lowest ΔHc. This was also reflected in the corresponding eutectic effect observed at 20–25 and 5–10°C, respectively. Palm‐based DAG‐enriched shelf‐stable margarine consisting of POL/PKO/PO‐DAG (42.5/42.5/15 w/w) was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SFC profile with commercial shelf‐stable margarine. Practical applications: In this study, valuable information about complicated interactions among the palm oil‐based diacylglycerol (PO‐DAG) and palm‐based oils with different FA chain length was obtained in the ternary system. These informative data may be useful in future exploitation of solid fat‐based DAG in blend with natural fats for various DAG‐enriched plastic fat products. Furthermore, Design Expert software was found to be a valuable tool to optimize the new fat blend formulation using the minimum number of blend preparation. By using this tool, assessment of complicated behaviour among the blend components through construction of the corresponding phase diagrams which are critical for optimization purposes as well as fat product development, would also be possible.     

In situ off-axis electron holography of metal-oxide hetero-interfaces in oxygen atmosphere

Off-axis electron holography has been extended to in situ observations in gas atmospheres. The Yttria-stabilized zirconia (YSZ)-Pt hetero-interface was characterized by electron holography at high temperature in a vacuum and in an oxygen atmosphere. Analysis of the phase shift profiles revealed high mobility of anions in the oxide in the vicinity of the interface in the oxygen atmosphere. This would compensate for any increase in the number of oxygen vacancies in YSZ through the metal interface.     

Full Rate Space Time Codes for Large Number of Transmitting Antennas with Linear Complexity Decoding

Among the specification of the 5G networks two crucial aspects are the support of fast mobility and high data rates. With fast mobility, the fading channels phenomenon become crucial, resulting in the need for multiple input/output channel to create spatial diversity. Space time codes (STC) have been shown to be well used with the Multiple Input Multiple Output channel. The Orthogonal STC (OSTC) family of codes is known to achieve full diversity as well as very simple implementation of the Maximum Likelihood (ML) decoder. However, it was also proven that with a complex symbol constellation one cannot achieve a full rate code when the number of transmitting antennas is larger than two. Quasi-OSTC (QSTC) can have full rate even for more than two transmitting antennas but with the penalty of decoding complexity which becomes severe if the constellation size is large. In order to tackle this inherent drawback of the OSTC/QSTC and to be able to support the 5G high data rate demand, we have come up with a different STC code that, when used with a new transmission and decoding methods, achieves full rate while maintaining linear complexity decoding for any number of transmit antennas. It can also be shown that when the transmitter knows the strongest channel (through minimal feedback) the code also achieves full diversity along with better error rate than the OSTC and the QSTC.     

A numerical investigation of conjugated-natural convection heat transfer enhancement of a nanofluid in an annular tube driven by inner heat generating solid cylinder

Laminar conjugate heat transfer by natural convection and conduction in a vertical annulus formed between an inner heat generating solid circular cylinder and an outer isothermal cylindrical boundary has been studied by a numerical method. It is assumed that the two sealed ends of the tube to be adiabatic. Governing equations are derived based on the conceptual model in the cylindrical coordinate system. The governing equations have been solved using the finite volume approach, using SIMPLE algorithm on the collocated arrangement. Results are presented for the flow and temperature distributions and Nusselt numbers on different cross sectional planes and longitudinal sections for Rayleigh number ranging from 10⁵ to 10⁸, solid volume fraction of 0‹φ‹0.05 with copper-water nanofluid as the working medium. Considering that the driven flow in the annular tube is strongly influenced by orientation of tube, study has been carried out for different inclination angles.     

Dual-Frequency Behavior of Stacked High <Emphasis Type="Italic">T</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> Superconducting Microstrip Patches

The dual-frequency behavior of stacked high T _c superconducting rectangular microstrip patches fabricated on a two-layered substrate is investigated using a full-wave spectral analysis in conjunction with the complex resistive boundary condition. Using a matrix representation of each layer, the dyadic Green’s functions of the problem are efficiently determined in the vector Fourier transform domain. The stationary phase method is used for computing the radiation electric field of the antenna. The proposed approach is validated by comparison of the computed results with previously published data. Variations of the lower and upper resonant frequencies, bandwidth and quality factor with the operating temperature are given. Results showing the effects of the bottom patch thickness as well as the top patch thickness on the dual-frequency behavior of the stacked configuration are also presented and discussed. Finally, for a better comprehension of the dual-frequency operation, a comparison between the characteristics of the lower and upper resonances is given.     

Fenton digestion of milk for iodinalysis

Iodine is an essential micronutrient especially important in the neurodevelopment of infants. Spot samples of urinary iodine (UI) are used as an epidemiologic index of adult iodine nutrition. Individual infant iodine nutrition is of vital importance, but infant urine is difficult to collect, much less a 24 h sample. Monitoring the intake provides a pragmatic solution for determining infant iodine nutrition. Because of the high solids content of milk and the possible existence of iodine in an organically bound form, sample digestion is obligatory. The U.S. Food and Drug Administration, for example, uses wet ashing by HClO(4); special precautions and fume hoods are required. We present a method of Fenton digestion of human and bovine milk samples and infant formula. No specialized equipment or hazardous reagents are used; measurement is made by isotope dilution inductively coupled plasma mass spectrometry. In Fenton digestion, Fe(II) and H(2)O(2) oxidizes the sample. In an interlaboratory study, excellent agreement (r(2) = 0.9934) was observed with results obtained by HClO(4) digestion and Sandel-Kolthoff kinetic colorimetry. Average recoveries of iodide, triiodothyronine, and thyroxine ranged between 100% and 101%. Following digestion, iodine was found to exist entirely as iodide. Control of pH is imperative if loss cannot be corrected for by isotope dilution. Loss was below 20% for all samples when the pH was between 2.25 and 2.5.