Water Network in Room-Temperature Ionic Liquid: <Emphasis Type="Italic">N,N</Emphasis>-Diethyl-<Emphasis Type="Italic">N</Emphasis>-Methyl-<Emphasis Type="Italic">N</Emphasis>-2-Methoxyethyl Ammonium Tetrafluoroborate

Crystal structures of room-temperature ionic liquid (RTIL)-H₂O mixtures are determined by the X-ray diffraction method. The RTIL is N,N-diethyl-N-methyl-N-2-methoxyethyl ammonium tetrafluoroborate, [DEME][BF₄]. At 0.9 mol pct H₂O, two kinds of superstructures occur simultaneously without a strain. Also, the volume of the unit cell is very small only at 0.9 mol pct additives. This relates to the composite domain structure, including a twin-related one, as an elastic anomaly. At other water concentrations, such an extraordinary behavior is not observable. By assuming a sublattice having an equivalent lattice constant, a water network at 1 mol pct H₂O is simulated using a Monte Carlo (MC) method. The network develops over the medium range in the simulation box.     

Reactive processing of polymer blends: Analysis of the change in morphological and interfacial parameters with processing

The change in morphology and interface quantities have been analyzed for an immiscible polymer blend during reactive processing. A model polymer/polymer combination, hydroxy-terminated poly(ε-caprolactone)/liquid rubber with α, ω-carboxy groups, was employed. The blend was subjected to light scattering measurements, ellipsometry, and gel permeation chromatography (GPC). Size reduction of the dispersed phase during processing was followed by a systematic decrease in the correlation distance ζ and an increase in the specific interfacial area Ssp, both by the Debye-Bueche plot of light scattering profiles. Also observed was the time variation of the volume fraction of interface V_λ estimated as a product of the Ssp and the interfacial thickness by ellipsometry. The changes in ζ, Ssp, and V_λ with processing were accelerated when a coupling agent,γ-aminopropyltriethoxysilane (APS), was added. The amount of block copolymer formed in-situ in the APS-loaded system was estimated by GPC with RI and UV detectors. For the size reduction kinetics in both APS-loaded and -unloaded systems, Rittinger's law was found to be applicable.     

Evaluation of vibration in many positions by SOM

We propose a method of evaluating the vibration of motor-operated electric tools (MOETs) by using a self-organizing feature map (SOM). The vibration spectrum is used to evaluate the MOET vibration. These vibration spectra are derived from 18 vibration data obtained by measurements on three different positions of a MOET. The spectra are then sent to the SOM network for the calculations. The vibration spectra are classified by the SOM, and calculations give the Euclidean distance from the weight vector in order to develop a quantitative evaluation. A statistic analysis of the Euclidean distance allows a quantitative evaluation of a MOET with respect to vibration stress and other relevant parameters.This work was presented, in part, at the 9th International Symposium on Artificial Life and Robotics, Oita, Japan, January 28–30, 2004     

Stereoselective determination of free warfarin concentration in protein binding equilibrium using direct sample injection and an on-line liquid chromatographic system

A new on-line high-performance liquid chromatography system was developed for the stereoselective determination of free drug concentration in drug-protein binding equilibrium. When a 40-300-microL portion of a sample solution containing 50-200 microM racemic warfarin (Wf) and 100-550 microM human serum albumin was directly injected into the internal-surface reversed-phase silica column, Wf gave a trapezoidal peak exhibiting a plateau region. The concentration in the plateau region was equal to the free Wf concentration in the initial sample solution. By the delivery of a portion (90 microL) of the eluent in the plateau region into the chiral separation column (Chiral AGP column) by column switching, the free concentrations of respective enantiomers of Wf were determined. The results agreed well with those obtained by the conventional ultrafiltration method. The precision was also confirmed by the within-run and day-to-day reproducibilities (coefficient of variation less than or equal to 3.05%, n = 5). The present method is simple and rapid and four sample solutions can be analyzed within 1 h without pretreatment.     

Michaelis-Menten analysis of immobilized enzyme by affinity capillary electrophoresis

Michaelis constant of enzymatic reaction was evaluated by affinity capillary electrophoresis using beta-galactosidase as a model enzyme and o- and p-isomers of nitrophenyl-beta-galactoside as substrates. The enzyme was immobilized on the inner surface of a fused-silica capillary by the covalent bonding through a bridging group, and the substrates were introduced into the capillary. The reaction products migrated electrophoretically toward the detection side (anodic side), while the unreacted substrates moved toward the injection side (cathodic side) on a slow electroosmotic flow generated by the weak negative charge of the immobilized enzyme. The initial velocity of the enzymatic reaction was estimated from the peak height of the product, and the Michaelis constant was calculated according to Lineweaver-Burk equation. The results (Km, 2.34 mM for o-isomer and 1.09 mM for p-isomer) were reproducible (RSD < 11.8%, n = 5). Although the estimated Michaelis constants were larger than the reported values measured in homogeneous solution, the ratio of the Michaelis constants of o-/p-isomers was in good agreement with the literature value. The present method required as low as a few microgram amount of enzyme and nanogram amount of substrate which is far smaller than those required in a conventional affinity HPLC.     

Heat capacities of NpN and AmN

The heat capacities of NpN and AmN were determined with the drop calorimetry method. The NpN and AmN samples were prepared by the carbothermic reduction of the respective dioxides. The heat capacity of NpN obtained was in good agreement with the reported values in the temperature range from 334 to 1067 K, which was close to those of UN and PuN. The heat capacity of AmN was obtained experimentally for the first time, which was slightly smaller than those of UN, NpN and PuN in the temperature range from 354 to 1071 K.     

Effects of seasonings on physical properties and MRI T2 map of cooked spaghetti

The effect of seasonings on the texture of cooked spaghetti was examined by sensory and shearing tests. Spaghetti tossed with sucrose, trehalose, salt, and monosodium glutamate and their mixture retarded deterioration of the firmness of spaghetti strands. To investigate the penetration of water and seasonings, maps of spin–spin relaxation time and their profiles from the center to the surface of a spaghetti strand were acquired by magnetic resonance imaging. The homogenization of moisture distribution in cooked spaghetti during holding was delayed temporarily by salt owing to a back current caused by the gradient of salt content on the surface immediately after tossing. Monosodium glutamate rapidly penetrated into spaghetti strands and caused water T₂ decrease possibly owing to the decreased mobility of water molecules in starch gel, whereas the sweeteners hardly altered the T₂ maps. Salt and monosodium glutamate are considered to retard more effectively the deterioration of firmness of spaghetti.     

Real-time monitoring system of tool breakage using Kalman filtering

In this paper, a real-time monitoring system of tool breakage, which measures the cutting torque from the spindle motor current, is described. The system uses an auto-regressive (AR)-model which is adapted for the measured signal using the Kalman filtering technique. The tool breakage is detected by monitoring the residual, that is, the deviation of the observed signal from the estimated value obtained by the AR-model. Additional processing of the residual is introduced to discriminate the signature of tool breakage from the effect caused by the marked change in the cutting condition. To reduce the computation time, the fast calculation algorithm is adopted for estimating the coefficient vector of the AR-model. The monitoring experiment has proven the effectiveness of the system in a milling operation.     

Loop recovery via ℋ︁∞-modified complementary sensitivity recovery for non-minimum phase plants

In order to recovery robust stability of a desirable state feedback system by output feedback, the desirable complementary function is approximated by a modified complementary function of the output feedback system by solving an ??^∞ norm-minimization problem. The modified complementary function is obtained by getting rid of non-minimum phase factors from the complementary function. Numerical examples show the superiority of this method to LQG/LTR method and other methods.