The preparation of O/W/O multiple emulsions by a one-step emulsification process was studied using an optical microscope equipped with a camera. The O/W/O multiple emulsions could be prepared by the introduction of two surfactants and two polymers. But when one of two polymers or water-soluble surfactant was not added, W/O emulsions with various size distributions were formed. Tween 20 added in water destabilizes W/O interfacial films formed by Span 80. At a result, the diffusion of 1-octanol into water droplets occurred more easily. Using a polymer in the continuous phase, the swelling of W/O interfaces was retarded but the use of two polymers in the continuous and discontinuous phases assisted the micelles mixed with oil molecules to diffuse into the core of aqueous droplets and remain. Moreover, the interaction between Tween 20 and PEG promoted coalescence of oil-swollen micelles in the water droplets. Depending upon the choice of water-soluble nonionic surfactants and polymers, three types of emulsion droplets were observed. Variation in the shapes of the droplets was due to differences in solubilization power of the surfactants. Also, the O/W/O multiple emulsions were stable for 8 h but most of the emulsions were at least partially broken after 24 h.

This study assessed analysis of N-nitrosamines by separation, identification, and quantification using a gas chromatography (GC) mass spectrometer (MS) with electron impact (EI) mode. Samples were pretreated by a automated solid phase extraction (SPE) and a nitrogen concentration technique to detect low concentration ranges. The analysis results by EI-GC/MS (SIM) and EI-GC/ MS/MS (MRM) on standard samples with no pretreatment exhibited similar results. On the other hand, the analysis of pretreated samples at low concentrations (i.e. ng/L levels) were not reliable with a EI-GC/MS due to the interferences from impurity peaks. The method detection limits of eight (8) N-nitrosamines by EI-GC/MS/MS analysis ranged from 0.76 to 2.09 ng/L, and the limits of quantification ranged from 2.41 to 6.65 ng/L. The precision and accuracy of the method were evaluated using spiked samples at concentrations of 10, 20 and 100 ng/L. The precision were 1.2~13.6%, and the accuracy were 80.4~121.8%. The R 2 of the calibration curves were greater than 0.999. The recovery rates for various environmental samples were evaluated with a surrogate material (NDPA-d14) and ranged 86.2~122.3%. Thus, this method can be used to determine low (ng/L) levels of N-nitrosamines in water samples.

A torque transmission system, which is composed of serveral gears and couplings, is flexible. Therefore, the transient vibration occurs when the motor velocity abruptly changes. To a transient vibration suppression, various control method have been proposed. Specially, one method of vibration suppression used disturbance observer filter. This method is torsion torque passing disturbance observer filter. By feedback of the estimated torsion torque, the vibration can be suppressed. In this paper, we used fuzzy controller. We proved of this approach is confirmed by simulation.

A simple analytical method to quantify formaldehyde in water at lower levels (µg/L) was developed using a high performance liquid chromatography (HPLC) and acetylacetone as a derivative reagent. Unlike conventional methods, no extraction and/or concentration were required. The derivative reagent was added into samples and reacted for 30 minutes at 80℃ prior to the analysis of formaldehyde using HPLC. The method detection limit and the limit of quantification for this method were 1.6 and 5.0 µg/L, respectively. This method also achieved high precision (0.6-3.0%) and accuracy (91.6-106.3%). The recovery rates for various environmental samples ranged from 92.0 to 115.2%.