Effects of polyglycerol esters of fatty acids and ethylene‐vinyl acetate co‐polymer on crystallization behavior of biodiesel

Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures.     

Effects of lipase,lipoxygenase, peroxidase and free fatty acids on volatile compound found in boiled buckwheat noodles

BACKGROUND: Relationships between buckwheat (Fagopyrum esculentum Moench) flour lipase, lipoxygenase and peroxidase activity, along with levels of individual free fatty acids (FFAs) and levels of headspace volatile compounds of boiled buckwheat noodles, were investigated for 12 different buckwheat varieties. Enzyme activities and FFA levels in flour were correlated with their respective varietal arrays of boiled noodle headspace volatile compounds, measured by gas chromatography–mass spectrometry. RESULTS: The volatiles hexanal, tentative butanal, tentative 3‐methylbutanal and tentative 2‐methylbutanal showed significant positive correlation with one another, indicating that they may be generated through similar mechanisms. These important volatile components of buckwheat flavor were also positively correlated with lipase and/or peroxidase activity, indicating that enzymatic reactions are important in flavor generation in boiled buckwheat noodles. On the other hand, pentanal, which showed no significant correlation with any enzyme activity, showed a significant positive correlation to the levels of C18:2 and C18:3 FFAs, suggesting the existence of a ‘non‐enzymatic’ and/or ‘uncertain enzymatic pathway’ for flavor generation in boiled buckwheat noodles. CONCLUSION: Lipase and peroxidase in buckwheat flour are important for flavor generation of boiled buckwheat noodles. This information is important for increasing desirable flavor of buckwheat products as well as for selecting varieties with improved flavor. Copyright © 2010 Society of Chemical Industry     

Detection of tris(2,4-di-tert-butylphenyl)phosphite (Irgafos 168, antioxidant in plastics) and its oxide in commercial frozen vegetables

Two peaks, A and B, detected in chromatograms of commercial frozen vegetable extracts during analysis of organophosphorus pesticide residues by GC-FPD, were identified as tris(2,4-ditert-butylphenyl)phosphite (Irgafos 168) and Irgafos 168 oxide, respectively, from their mass spectra. Irgafos 168 is used as an antioxidant in plastics, and there has been no report of its detection in foods. We analyzed Irgafos 168 and its oxide in 38 samples of commercial frozen vegetables, and they were detected from 4 samples (0.02-0.80 microgram/g as total amount of Irgafos 168 and its oxide).     

Development of effective detection method for Coxiella burnetii in mayonnaise by real-time PCR and investigation of C. burnetii contamination in commercial mayonnaise in Tokyo

A PCR method for the effective detection of Coxiella burnetii in commercially available mayonnaise was developed. Sample preparations were isolated from 50 g portions of each mayonnaise product by four successive extraction steps in phosphate buffer with 2.0 M NaCl. These extracts were then centrifuged at 20,000 x g for 60 min. DNA was isolated from the solution containing the precipitate with a commercial kit, and amplified quantitatively using real-time PCR that targeted the com1 region of C. burnetii. The recoveries of C. burnetii from 2 kinds of commercial mayonnaise specimens, with a baseline control of 1 x 10(7) particles of the Nine Mile phase II strain, were 85.0 +/- 6.0% and 72.0 +/- 0.4%, respectively. The determination limit of this method was 500 C. burnetii particles per 50 g of mayonnaise. The DNA specimens isolated from 50 different commercial mayonnaise samples sold in Tokyo using this method were amplified using both nested PCR and real-time PCR. No contamination by C. burnetii was detected in any of the mayonnaise samples.     

Ferroelectric properties of ultrathin films of Nylon 11

Ferroelectric properties of ultrathin films of Nylon 11 were investigated. The thickness was in the range of 25 to 55 nm. Ferroelectric response was largely affected by thermal annealing and following cooling conditions. Thermal annealing at higher temperature followed by quenching in liquid nitrogen gave larger remanent polarization and smoother surface, whereas cooling down in an ambient atmosphere caused smaller remanent polarization and rough surface. Surface roughness strongly affected the polarization reversal and remanent polarization. Hydrogen bonding in crystal was also significantly related to the polarization reversal and thus remanent polarization.     

Impedance calculation of a single-layer air-core coil by means of resonant modal theory

A method for calculating the impedance of a single-layer air-core coil is developed. The coil is expressed by a pair of multiphase distributed-parameter lines. The nodal voltages within the coil are transformed into a modal domain by applying an eigen theory. The transformation diagonalises the nodal equation expressed by Y-parameters of the distributed-parameter lines. The method permits composition of an equivalent circuit of the air-core coil. The accuracy of the model is easily tuned by adjusting the number of eigenvalues taken into account. The choice of the eigenvalues is carried out by the voltage distribution along the wire of the coil. The dominant mode is obtained by an assumption that the voltage distribution is uniform. This mode gives the lowest antiresonant frequency of the coil. The other distribution patterns are assumed to be sinusoidal. The second dominant mode corresponds to the lowest space frequency among the distribution patterns. In general, there is no relation between the order of the calculated eigenvectors and the voltage distribution. Its order is sorted according to the voltage distribution using an initial eigenvector matrix. The accuracy of the impedance increases with the number of eigenvalues, which are taken into account according to the sorted order. A simplified lumped-parameter equivalent circuit of the coil is derived for the major modes. The simplified model is able to represent not only antiresonances but also resonances of an air-core coil. The accuracy of the proposed model is confirmed by comparisons with measured and theoretical results.     

An impedance measurement of a small‐capacitance circuit using transient responses for lightning surge analysis

A method to measure a small capacitance with its loss resistance using a set of transient current waveforms is proposed in this paper. The parameters are obtained from the time constants in the time domain. The method has high resistance to extraneous noise, because a time‐to‐frequency transformation, which is sensitive to noise, is not required. The transient current waveforms are obtained by a voltage or current source, a current transformer, and a waveform recorder. The measured capacitance by the proposed method is not affected by the capacitance of the voltage probe, because it is obtained without any voltage information. The sheath surge impedance of the current injection cable, which is indispensable for the transient measurement, is corrected. The application of the method has the advantage in that it allows the modeling of a fast transient of a power apparatus, comparing it with the steady‐state measurement using an impedance measuring instrument. The proposed method is applied to create an equivalent circuit between electrodes implanted into a piece of wood, and its reliability is confirmed by comparison between the measured and calculated results. Stray capacitances of a miniature circuit breaker are also measured, and the results show that the proposed method is applicable to equipment in power systems. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Simultaneous removal of NO/sub x/, SO/sub x/, and CO/sub 2/ at elevated temperature using a plasma-chemical hybrid process

In previous studies, the authors confirmed that the plasma-chemical combined hybrid process for controlling NO flue gas emission was extremely effective and economical in comparison with the conventional selective catalytic reduction (SCR) system and other technologies. In the present study, we carried out experiments on the simultaneous removal of NO/sub x/ and SO/sub x/ at elevated temperature using the plasma-chemical hybrid process. A series of experiments was performed to quantify all the reaction byproducts such as N/sub 2/O, CO, HNO/sub 2/, HNO/sub 3/, NO/sub 3//sup -/, and SO/sub 4//sup -/ to evaluate the simultaneous NO/sub x/ and SO/sub x/ removal efficiency. The oxidation from NO to NO/sub 2/ without decreasing NO/sub x/ concentration (i.e., minimum reaction byproducts) and with least power consumption is the key for the optimum operation of the plasma reactor. The produced NO/sub 2/ was totally converted to N/sub 2/ and Na/sub 2/SO/sub 4/ with Na/sub 2/SO/sub 3/ or Na/sub 2/S with and without NaOH using the barrier-type packed-bed plasma reactor followed by the packed-column chemical reactor. The NO/sub 2/ reduction was more effective for Na/sub 2/S than Na/sub 2/SO/sub 3/ but produces H/sub 2/S with Na/sub 2/S. For both cases at least five times the stoichiometric amount of chemicals were required for complete NO/sub 2/ reduction. Nearly 100% of NO/sub x/ and SO /sub 2/ and 40% Of CO/sub 2/ simultaneous removal were achieved with less than 5 ppm of N/sub 2/O and CO. The operating cost was less than 1/4 the SCR process. The additional SO/sub 2/ treatment system can be eliminated.     

Texture and Formation Mechanism of Fibrous Calcium Hydroxyapatite Particles Prepared by Decomposition of Calcium–EDTA Chelates

The texture of fibrous calcium hydroxyapatite (Ca₁₀-(PO₄)₆(OH)₂, CaHAP) particles that were prepared by the decomposition of calcium–ethylenediaminetetraacetic acid (calcium–EDTA) chelates at 100°C under various pH conditions (pH values of 5–10) was investigated by various means. Well-crystallized fibrous CaHAPs were produced at pH .6. The stoichiometry of the CaHAPs with a chemical formula of Ca_{10− x} (HPO₄) _x (PO₄)_{6− x} (OH)_{2− x} (H₂O) _x was improved by increasing the decomposition pH. All the CaHAPs had unit-cell dimensions of a = 0.9436 ± 0.0003 nm and c = 0.6881 ± 0.0006 nm, exhibiting an enlarged a value. The finding of mesoporosity of CaHAPs by nitrogen gas (N₂) adsorption measurement indicated that the CaHAPs were produced by an agglomeration of primary particles. Furthermore, the nonstoichiometric CaHAPs that formed at pH 6 developed ultramicropores, which were accessible to water (H₂O) molecules but not to N₂ molecules, by the elimination of H₂O molecules that were adsorbed in interstices of primary particles in less-orderly crystallized CaHAPs and/or by dehydration of HPO₄²⁻ groups. These findings by gas adsorption techniques could give evidence for the agglomeration mechanism to attain a polycrystalline CaHAP, although they exhibited good crystallinity with large size.