Line Reactor Research Articles

Determination of Glucose in Plasma Using Immobilized Enzymes in a Flow System.

Glucose was determined using an apparatus containing an enzyme reactor in a flow line. The enzymes used for glucose assay were hexokinase and glucose-6-phosphate dehydrogenase. NADH formed by enzymatic reactions was fluorometrically detected. The calibration curve for glucose was linear within the range of 0.2-50μM (r=0.9996), and the detection limit was 0.1μM (S/N=3). This method was applied to the analysis of glucose in plasma. No influence of sodium fluoride on the activities of immobilized enzymes was observed. Recovery of glucose added to plasma or serum was found to be in the range of 98 to 106%. We investigated the correlation between the glucose content determined by other methods and that determined by the present method. A linear relationship was observed between that determined by the present method and that by both the glucose oxidase-electrode method (y=0.986x-4.6, r=0.9993) and the soluble enzyme method (y=1.004x+1.3, r=0.9982).

Glucose Determination Using a Flow System with Enzyme Reactor and Application to Analysis of Glucose Content in Beverages

Glucose was determined using an apparatus containing an enzyme reactor in a flow line. The enzymes used for glucose assay were hexokinase and glucose-6-phosphate dehydrogenase. NADH formed by enzymatic reactions was fluorometrically detected. The optimal concentrations of ATP and NAD in the carrier were determined. Of the buffers examined for use as a carrier medium, triethanolamine buffer was found to be the most favorable and the optimal pH of this buffer was pH 7.0. Under these optimal conditions, the calibration curve for glucose was linear in the range of 2.0-200μM(r=0.999). Detection limit was 1.7μM(S/N=3).This method was applied to the analysis of glucose in several beverages. Glucose content determined by the present method agreed with that determined by a commercially available test-kit method. The methods for the preparation of immobilized enzymes were examined to retain the activities of enzymes.

Design considerations for 12-pulse diode rectifier systems operating under voltage unbalance and pre-existing voltage distortion with some corrective measures

In this paper, design considerations for twelve-pulse diode rectifier systems operating under utility voltage unbalance and pre-existing harmonic voltage distortion are discussed. For a twelve-pulse diode rectifier system connected in parallel to feed a common DC link via an interphase transformer, it is shown that a small amount of impedance mismatch, utility voltage unbalance or pre-existing voltage distortion drastically affects the current sharing capability of the rectifier bridges. This, in turn, generates additional uncharacteristic and characteristic harmonics thereby increasing the THD. In order to mitigate these effects and ensure proper operation of diode rectifiers, specially designed line reactors termed harmonic blocking reactors (HBRs) are introduced. Analysis and design procedures for HBRs are discussed. Simulation results illustrate improved performance. Experimental results from a laboratory prototype system show close agreement with theory.

Determination of carbosulfan in oranges by high-performance liquid chromatography with post-column fluorescence.

High-performance liquid chromatography equipped with post-column fluorescence derivatization provides an automated and specific analytical method for pesticide determination. Carbosulfan, a carbamate pesticide, can be analysed utilizing an existing and proven carbamate system after the addition of one additional hydrolytic reactor in-line. Extraction of this compound from citris crops requires careful handling owing to the volatility and unstable nature of the analyte in acid conditions. This paper describes the necessary instrument modifications and presents a method for carbosulfan extraction. Analyses of orange homogenates were performed rapidly with recoveries of between 66 and 98% for residue levels between 0.03 and 0.25 micrograms kg-1.

Functional differentiation and primary metabolism of mouse mammary epithelial cells in extended-batch and hollow-fiber culture

Growth, expression of functional differentiation (as characterized by synthesis and secretion of milk proteins), and primary metabolism were studied for a mouse mammary epithelial cell line, COMMA-1D, in extended-batch and hollow-fiber reactor cultures. Batch cultures were performed on Costar polycarbonate membrane inserts, allowing basal and apical exposure to medium. Protein production was induced in both batch and hollow-fiber cultures in hormone-supplemented medium. In batch cultures, high levels of protein production and secretion were maintained for 18 days. Once differentiation was induced, the rate of deinduction was low, even in medium containing epidermal growth factor (EGF) and serum; cells continued to express and secrete proteins for at least 12 days after prolactin and hydrocortisone were removed. Cells in both batch and hollow-fiber cultures were highly glycolytic and exhibited low rates of glutaminolysis. In batch culture on membrane inserts, cells showed polarized metabolism between the apical and basal side, maintaining significant gradients of glucose and lactate. Medium hormonal composition and subsequent differentiation affected both glucose uptake and lactate yield for COMMA-1D in batch culture.

Remarks upon the modelling of heterogeneous catalytic reactors – the single fluid‐solid cases

AbstractTo our benefit, the modelling of fluid‐solid catalyzed reaction‐reactor systems has long been the keen concern of Hanns Paul Hofmann. In the light of his instruction we remark upon key aspects of modelling for the (a) fixed bed (b) fluid bed and (c) moving bed/transport line reactors. There emerges from such analyses a properly renewed awareness of the need for a more sophisticated respect for reliable physical‐chemical data. As Hanns has taught us, our models are no btter than our data.

Noise analysis of a zero power critical line reactor using Langevin's technique

Noise analysis of a critical, infinite-length, zero-power line reactor is given using the Langevin technique. A one-speed model is used and delayed neutrons are ignored. Stochastic analysis is carried out starting from the Boltzman equation with the assumption that neutrons move only in both directions in the line reactor. The power spectrum of neutron fluctuations is obtained and compared with that computed from diffusion approximation. Exact expressions for auto and cross-power spectrums of non-fission neutron detectors' outputs are also obtained.

Pyrolysis of coal liquids

The pyrolysis of process recycle solvent derived from Western Kentucky coal via the SRC-II coal liquefaction process was investigated to ascertain the effect of residence time and temperature on the production of olefins. The study was made using an alonized transfer line reactor operating at temperatures of 650 and 730 °C, essentially atmospheric pressure, and residence times up to 0.13 s. A comparison is made with previously published results for the pyrolysis of hydrotreated COED light and heavy coal liquids (subsequently referred to as COED light and heavy oils, respectively) derived from Western Kentucky coal and steam pyrolysis of a hydrogenated fraction of SYNTHOIL derived from Western Kentucky coal. Results indicate that in each case the preferential pyrolysis of the saturate fraction occurs under convential pyrolysis conditions. Ethylene, propylene, and methane were the dominant gas products in all cases. The liquid pyrolysates from the COED oils and SRC-II recycle solvent had lower H C ratios and heating values than their respective feedstocks. Mass spectroscopic analysis of the liquid pyrolysates in each case revealed the presence of polycyclic aromatics that were not present in the individual feedstocks. This trend which increased with temperature is indicative of cyclization and/or recombination of free radicals during pyrolysis. It is therefore surmized that the yields of light olefins from primary coal liquefaction products can be improved by partially hydrogenating them prior to pyrolysis. Alternatively, sufficient hydrogen can be provided in the vicinity of cracking to suppress retrogressive reactions which lead to the formation of coke. The pyrolysis of COED oils and SRC-II recycle solvent was found to follow first-order irreversible kinetics. The activation energy for the pyrolysis of the COED light and heavy oil was found to be 76.1 and 70.85 kJ g-mol −1, respectively.

Pyrolysis of Western Kentucky Heavy Oil Using a Transfer Line Reactor

Pyrolysis of Western Kentucky Heavy Oil Using a Transfer Line Reactor

Pyrolysis of Western Kentucky COED Light Oil in a Transfer Line Reactor

Pyrolysis of Western Kentucky COED Light Oil in a Transfer Line Reactor

A Kinematic Model for Catalytic Cracking in a Transfer Line Reactor

A Kinematic Model for Catalytic Cracking in a Transfer Line Reactor

Performance of a 5 kVA synchronous generator with an optimal excitation regulator

The feasibility of applying optimal control to the excitation of a synchronous generator is examined in the laboratory, using a 5 kVA 3-phase alternator connected through line reactors to an infinite busbar. The regulator is a small digital computer, which monitors the states of the system and computes the control signal applied to an electronic amplifier exciting the alternator field. The feedback gains of the optimal regulator satisfy a simple quadratic cost function. These are calculated offline for a grid of operating points in the complex power plane, and stored in the controlling computer. The gains used at any particular operating point are those corresponding to the nearest gridpoint. Comparisons of predicted and actual small-disturbance responses are made for leading-power-factor operation well beyond the open-loop stability limit, and, for low real power, beyond the closed-loop limit with voltage feedback alone.

Influence of Shunt Reactors on Switching Surges

On the basis of transient network analyzer studies this paper discusses the influence of EHV shunt reactors on the overvoltages occurring during breaker operations on transmission systems. The comparative importance of line losses and reactor losses on the decay of the trapped charge voltages that oscillate with frequencies dictated by line capacitances and shunt reactor inductances is analyzed. Emphasis is placed on the influence on these oscillations of different types of faults and line asymmetries.

Dynamic braking of 3-phase motors by capacitors

When a series capacitor is introduced in one of the supply lines of a 3-phase induction motor working under normal load conditions, the torque developed by the motor is considerably reduced. If the speed falls below a certain value, the machine develops braking torque and decelerates to standstill and may even run in the opposite direction. This aspect was touched upon in a previous paper1 and is now investigated further, both theoretically and experimentally. Applying the method of symmetrical components, the current and torque equations are obtained for the machine during the braking period. It is suggested that the driving torque developed by the machine at high speeds, even with the introduction of the series capacitor, can be avoided either by working the machine as a self-excited induction generator or by introducing a suitable series reactor in another supply line. These methods of dynamic braking are compared with the conventional plugging method.

Actual Tests of the Universal Arc Suppressing Reactor in the Shinanogawa Transmission Line of Ministry of Railways

Actual Tests of the Universal Arc Suppressing Reactor in the Shinanogawa Transmission Line of Ministry of Railways