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Disposable shaking bioreactors are a promising alternative to other disposable bioreactors owing to their ease of operation, flexibility, defined hydrodynamics and characterization. Shaken bioreactors of sizes 20 L and 50 L are characterized in terms of heat transfer characteristics in this research work. Water and an 80% glycerol–water system were used as fluid. Results indicated large heat generation due to shake mixing which was observed by temperature difference between the fluid inside the vessel and the surrounding air outside the vessel. Maximum temperature difference of ca. 30 K was encountered for a 50 L vessel, at 300 rpm and 20 L filling volume. Outside heat transfer rate was governing the overall heat transfer process. Lateral air flow did increase heat transfer rates to large extent. An empirical correlation of overall heat transfer coefficient was obtained in terms of filling volume, rotational speed and lateral air flow rate. However, as the vessel thickness increased, the overall heat transfer process was limited by vessel wall resistance.

TiO 2 /Cu 2 O heterojunction solar cells were fabricated by two low-cost chemical techniques. TiO 2 thin films were fabricated by electrophoretic deposition using a TiO 2 sol solution. An approximately 0.5 μm-thick film was deposited with a deposition time of 1 s. Cu 2 O thin films were fabricated by electrodeposition using an aqueous CuSO 4 solution with pH adjusted to 12.5. The heterojunction solar cells were fabricated by first depositing TiO 2 on the indium-tin-oxide glass substrate, and then depositing Cu 2 O on TiO 2 . The cells were annealed in air atmosphere. A conversion efficiency of about 0.1% was achieved after annealing at 120 °C.

Non-isothermal miscible displacements in a radial Hele-Shaw cell were experimentally investigated using a scheme in which room temperature liquids of relatively high viscosity were displaced by high-temperature (80 °C), less-viscous liquids. Fundamental characteristics have been presented regarding how the effect of a non-isothermal field on miscible displacement patterns varies in terms of factors such as the viscosity ratio of the more- and less-viscous liquids at 20 °C, M20, the rate of an increase in the pattern’s area, R, and the gap width of the cell, b. The concept of area density was used to quantitatively evaluate the effect of the non-isothermal fields on the patterns. We have found that the effect of the non-isothermal field on the patterns does not monotonically vary with M20 and b. In contrast, it increases with R in the present experimental condition. The experimental results can be explained by introducing an assumption in which heat is transferred mainly to the plates of the cell, in other words, the temperature of the more-viscous liquid remains constant, whereas that of the less-viscous liquid spatiotemporally decreases and the viscosity of it increases along with the temperature decrease. Visualization of non-isothermal field in the cell has been done by means of a thermo sheet and the results support the assumption mentioned above.

Disposable bioreactors are increasingly used in bioprocess development of animal cell cultures. However, the engineering parameters of the present disposable bioreactors are very difficult to characterise. Characterisation of any bioreactor is important to evaluate the suitability of operating conditions and absolutely necessary for successful scale-up. In this research work, an attempt is made to validate a characterisation method which is simple and can be used for any given volume of disposable bioreactors larger than 2 L. Two evaluation methods, namely the temperature method and the well established torque method were used for determination of power consumption in 2 L and 20 L disposable shaken bioreactors. The trend of the values of power consumption was shown with respect to shaking frequency and filling volume. Results indicate that quite reasonable values of power consumption can be obtained by the temperature method and the torque method, which are in good agreement with each other (error

Portopulmonary hypertension (P-PHT) is sporadically found in cirrhosis patients who have portal hypertension. We retrospectively investigated the clinical features of six patients with P-PHT and compared their hemodynamics and arterial oxygenation with data from 60 cirrhosis patients without pulmonary hypertension (non-PHT cirrhosis) admitted to our department. The mean pulmonary artery pressure and pulmonary vascular resistance index of P-PHT patients ranged from 25 to 57 mmHg and from 399 to 1405 dynes s cm−5 m−2, respectively, and their arterial oxygenation was impaired. The systemic vascular resistance and cardiac index of P-PHT patients were similar level to those of patients with non-PHT cirrhosis. We found 10 patients with non-PHT cirrhosis in whom pulmonary vascular resistance exceeded the critical level for pre-capillary pulmonary hypertension (120 dynes s cm−5). These patients showed a distinctive hemodynamic profile, including a decrease of cardiac output due to contraction of the plasma volume and resultant elevation of systemic vascular resistance. However, the decrease of cardiac output contributed little to the elevation of pulmonary vascular resistance. Our findings suggested that certain factor(s) were acting to raise pulmonary vascular tone in these patients, which might cause chronic damage to the pulmonary vascular bed, leading to the onset of pulmonary hypertension.

The application of disposable equipment is a new trend in bioprocessing. Liu and Hong (C.M. Liu, L.N. Hong, Development of a Shaking Bioreactor System for Animal Cell Cultures, Biochem. Eng. J. 7 (2) (2001) 121–125) have shown that the cultivation of animal cell cultures in large plastic shaking vessels of up to 56 L volume resulted in good performance in terms of product concentration. In order to characterize this type of reactor from a chemical engineering view point, the power consumption of a large rotary shaking vessel (20 L) by a temperature method was measured. It was shown that heat insulation of the large vessel is not required to measure power consumption and, therefore, a simple experimental setup could be employed. The power consumption per unit volume in the large vessel was found to be in the same range (≤10 kW/m3) as that in small shaking flasks (

An N-medium containing carboxymethyl cellulose (CMC) was applied to an air-lift type bioreactor culture of grape (Vitis vinifera cv. Bailey alicant A.) callus, and anthocyanin production was investigated. Grape callus grew well at an air flow rate of 80 ml/min and anthocyanin production was significantly increased in the N-medium, reaching 17 mg/l after 7 d of culture. The anthocyanin content of the N-medium was about two times higher than that of the conventional medium without CMC. The effect of air flow rate was also investigated within the range from 40 to 160 ml/min. A twofold increase in anthocyanin content was obtained at all the air flow rates tested in the N-medium. The distribution of grape callus size obtained after 7 d of the bioreactor culture was investigated. The average callus size was 490 mum which was 1.6 times larger than that obtained in the conventional medium. It was found that large calli with a relatively high anthocyanin pigment content were formed in the bioreactor culture using the N-medium. The fluid dynamics in the bioreactor was also investigated at three points (top, middle and bottom) in the bioreactor by laser doppler velocimetry. The average axial velocity of the circulated medium was 0.4 times lower than that of the conventional medium while their average radial velocities were almost the same (zero). The standard deviation of radial velocity fluctuation in the N-medium was also 0.4 times less than that in the conventional medium. These results suggest that turbulent flow occurred in the bioreactor culture using the conventional medium and the degree of turbulent flow decreased significantly when 0.8% CMC was added to the medium to prepare the N-medium. A change of the flow pattern is considered to be the cause of the decrease in hydrodynamic stress, resulting in enhanced pigment production due to the enlargement of the callus.

Power consumption in a non-baffled agitated vessel with a double impeller was measured over a wide range of Reynolds number from laminar to turbulent flow regions. The power correlation for the double impeller was derived from the modification of the power correlation for a single impeller proposed by the authors. The power consumption in a baffled vessel was only measured in the turbulent flow region. The power consumption for the double impeller has the maximum value, which was almost twice the power consumption for the single impeller at larger ratio of impeller clearance to liquid depth than 0.35, and it took the minimum value at the impeller clearance ratio of 0.18–0.25. Mixing time in a baffled vessel with some types of double impeller was measured in the turbulent flow region using the decolorization method of sodium thiosulfate and iodine reaction. The minimum mixing time was observed at 0.1–0.2 of the ratio of impeller clearance to liquid depth for the two-stage paddle system, and 0.5–0.7 for the double impellers constructed with the pitched blade paddle. The relationship of mixing time to power consumption for the double impeller system coincided with that for a single impeller at the impeller clearance taking the minimum mixing time.

The performance of a shaking vessel-type bioreactor with a current pole at its central axis was examined experimentally with respect to particle dispersion, power consumption, and solid-liquid mass transfer coefficient. The current pole improved the particle dispersion without an increase in power consumption and reduced the critical circulating frequency for complete suspension. The mass transfer coefficient with a current pole had the same value as that without a current pole above the critical circulating frequency for complete suspension. The shaking vessel-type bioreactor with a current pole was thus very suitable for the mass production of regenerated plantlets from fragmented horseradish hairy roots.