Gas Interchange between a Bubble and Continuous Phase in Gas-Soild Fluidised Bed

The mechanism of gas interchange between a bubble and the continuous phase was investigated by blowing a bubble of visible brown NO₂ gas into two dimensional fluidised bed. From this investigation, it was found that the gas interchange occurred by the diffusion and by the flow out of gas from the cloud which was caused by variations of velocity and diameter of bubble. Based on the above transfer mechanism, a model for gas interchange was suggested and the gas interchange coefficient was calculated. Furthermore, gas interchange coefficients were obtained by measuring the change of the concentration of a CO₂ gas bubble at two different heights in the bed. The gas interchange coefficients calculated from the model coincided well with that obtained from experiments

The Motion of Particles Caused by a Bubble in Gas-solid Fluidised Bed

The motion of particles caused by a single bubble which is blown into a two-dimensional fluidised bed has been studied. A drift line which is shown when a bubble has passed through the bed is obtained as a generalized curve. The experimental results can be explained fairly well by the authors' model. The model is as follows. 1. The motion of particles is assumed as the motion of perfect fluid caused by the motion of a circular cylinder in the perfect fluid. 2. There is an imaginary wall at the distance of the diameter of bubble below from the center of the moving bubble and it moves upwards with the same velocity as the bubble

Gas Interchange between Bubble Phase and Continuous Phase in Gas-Solid Fluidised Bed at Coalescence

By investigating the phenomena of coalescence of bubbles from the view point of gas interchange, the mechanism of interchange at coalescence in the case of two bubbles on the same vertical line was explained with the aid of Murray's method which gave the gas stream function. CO₂ gas bubbles were blown into a two dimentional air-fluidised bed at the point of minimum fluidisation through a single nozzle. The concentration of the bubble and of the continuous phase was measured and the gas interchange coefficient was obtained. From it, the amount of gas that flowed out from the cloud was obtained and it coincided fairly well with that obtained from the gas stream line. Although the experimental system was a special case where bubbles were formed only from a single nozzle, the method for obtaining the gas interchange coefficient, that includes the effect of coalescence, was explained if the distribution of the frequency and the rising velocity of the bubble were known

Amoxicillin-Induced Eosinophilic Pneumonia with Granulomatous Reaction: Discrepancy between Drug-Induced Lymphocyte Stimulation Test Findings and the Provocation Drug Test

<p/> <p>A 59-year-old man was admitted to the hospital with pulmonary infiltration, fever, erythema, and eosinophilia. Two weeks before admission, he received amoxicillin, acetaminophen, and shoseiryu-to (a Japanese herbal medicine) for a common cold. Bronchoalveolar lavage was performed, and an increased number of eosinophils was recovered. Transbronchial biopsy specimens showed granuloma and interstitial thickening with eosinophils and lymphocytes. Drug-induced eosinophilic pneumonia was suspected, so all drugs were discontinued. The symptoms and infiltration shadow disappeared. A drug-induced lymphocyte stimulation test (DLST) was positive for acetaminophen but not for amoxicillin. In contrast to the DLST, a provocation test revealed that amoxicillin induced the drug allergy. A very striking observation was the coexistence of pulmonary eosinophilia and granulomatous lung infiltrations. In addition, there was a discrepancy between the DLST and provocation test findings. To our knowledge, there is no previous report of drug-induced eosinophilic pneumonia with a granulomatous reaction.</p

Behaviours of Bubbles in the Gas-Solid Fluidized-Beds

The size, shape and rising velocity of bubbles and also particle concentration in bubbles which appeared in the air-solid fluidized bed were investigated by photography, X-ray photograpy, X-ray cinematography and capacitance method. The results were that the bubbles had nearly the shape of spherical cap and there were few particles in the bubbles. Although the rising velocity of the bubble was affected largely by other bubbles, it was proportional to the square root of the vertical bubble length and the bubbles became large with the process of repetition of coalescence and redispersion

Lipase-Catalyzed Synthesis of Unsaturated Acyl L-Ascorbates and Their Ability to Suppress the Autoxidation of Polyunsaturated Fatty Acids

ABSTRACT: L-Ascorbic acid and various polyunsaturated fatty acids (PUFA) were condensed at 55°C by the immobilized lipase Chirazyme L-2 in dry acetone to produce the unsaturated acyl ascorbates. The PUFA moieties of the products were much more resistant to autoxidation at 65°C and nearly 0% relative humidity than the corresponding unmodified PUFA. The effects of the molar ratio of ascorbic acid or linoleoyl ascorbate to linoleic acid on the autoxidation of linoleic acid were examined. The autoxidation of linoleic acid was effectively suppressed at molar ratios greater than or equal to 0.2 when either ascorbic acid or linoleoyl ascorbate was mixed with linoleic acid. The addition of lauroyl ascorbate, synthesized through the enzyme-catalyzed condensation of ascorbic acid and lauric acid in acetone, to docosahexaenoic acid also significantly suppressed the autoxidation of docosahexaenoic acid at molar ratios of ≥0.2. Paper no. J9826 in JAOCS 78, 823-826 (August 2001). KEY WORDS: Acyl ascorbate, L-ascorbic acid, autoxidation, condensation, immobilized lipase, polyunsaturated fatty acid. Much attention has been paid to the use of polyunsaturated fatty acids (PUFA) as components in foods (1). However, PUFA are susceptible to autoxidation (2,3), and the autoxidation causes deterioration of the foods. L-Ascorbic acid is a hydrophilic antioxidant with a strong reducing ability. The lipase-catalyzed synthesis of acyl ascorbate in a solid-phase system (4) or in an organic solvent (5-9) has been reported. However, its ability to suppress lipid autoxidation has not been reported. In a previous paper (10), we reported the synthesis of 6-O-eicosapentaenoyl L-ascorbate by the lipase-catalyzed condensation of eicosapentaenoic acid and L-ascorbic acid in acetone and compared its autoxidation process to that of the unmodified eicosapentaenoic acid. In the work described in this paper, some PUFA L-ascorbates were synthesized using an immobilized lipase from Candida antarctica, Chirazyme ® L-2, and their autoxidation processes were then observed. The PUFA used were linoleic, α-linolenic, γ-linolenic, arachidonic, and docosahexaenoic acids. The effect of the molar ratio of unmodified L-ascorbic acid or linoleoyl ascorbate to linoleic acid on the suppression of the autoxidation of linoleic acid was examined. We previously reported the lipase-catalyzed condensation of ascorbic acid with various medium-chain fatty acids having carbon numbers of 6, 8, 10, and 12 in acetonitrile (11). Therefore, the ability of lauroyl ascorbate to suppress the autoxidation of docosahexaenoic acid was also evaluated in the present work. EXPERIMENTAL PROCEDURES Materials. γ-Linolenic and docosahexaenoic acids were supplied by the Maruha Corporation (Tokyo, Japan), and their purities were both greater than 95% based on gas chromatographic (GC) analysis. L-Ascorbic acid, linoleic acid, acetone, and hexane were purchased from Nacalai Tesque (Kyoto, Japan). α-Linolenic, arachidonic, and lauric acids were purchased from Sigma Chemical (St. Louis, MO). Immobilized lipase from C. antarctica, Chirazyme ® L-2 c.-f. C2, was obtained from Roche Molecular Biochemicals (Mannheim, Germany). The enzyme is the same as Novozym ® 435 according to the manufacturer. Soybean oil was purchased from Wako Pure Chemical Industries (Osaka, Japan). Condensation reaction. Acetone was first dehydrated by adding 5 Å molecular sieves. The water content of the acetone was about 0.01% (vol/vol), and was determined for each experiment by a Karl-Fischer titration. L-Ascorbic acid (0.125 mmol) and a PUFA [linoleic acid (0.577 mmol)], γ-linolenic acid (0.600 mmol), arachidonic acid, (0.638 mmol), α-linolenic acid (0.611 mmol), and docosahexaenoic acid (0.648 mmol)] were weighed into an amber glass vial with a screw cap, and 200 mg of Chirazyme L-2 and 2.5 mL of dehydrated acetone were added to the vial. The headspace of the vial was filled with nitrogen, and the vial was tightly sealed. The vial was then immersed in a waterbath at 55°C with vigorous shaking to commence the condensation reaction. At appropriate intervals, 10 µL of the reaction mixture was taken and mixed with 50 µL of a 50 mM solution of toluene in high-performance liquid chromatography (HPLC) eluent [acetonitrile/tetrahydrofuran/0.1% (vol/vol) phosphoric acid (50:22:28 by vol) as the internal standard for the HPLC analysis and then with 40 µL of HPLC eluent. The analysis was carried out by HPLC with a YMC-Pack C8 column (4.6 mm × 250 mm; YMC Inc., Kyoto, Japan) and an ultraviolet (UV) detector (245 nm). The mixture (20 µL) was applied to the column and eluted with the eluent at 1.5 mL/min. The retention times o

Effect of oil droplet size on activation energy for coalescence of oil droplets in an O/W emulsion.

Published online: 12 May 2015The activation energy of a reasonable order of magnitude was estimated for the coalescence of oil droplets in an O/W emulsion by formulating the balance of forces acting on a droplet that crosses over the potential barrier to coalesce with another droplet by the DLVO theory and Stokes' law. An emulsion with smaller oil droplets was shown to be more stable