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An approach is proposed for predicting the change in the reliability of reactor pressure vessels of nuclear power plants. A computer program was used to perform a series of calculations for finding the invariant classification as a function of the degree of stochastic action on a time interval. A stable solution was obtained by modeling the stochastic action with a root mean square deviation of up to 15% of the instantaneous normalized value of the parameter. The proposed approach is not universal, but has the advantages of easily correcting forecast data, avoiding extreme conservatism, and usability at all stages of design, fabrication, assembly, and operation. 7 refs., 1 tab.

Abstract In this study, crude cellulose derived from cornstalk, after bleaching, was used as raw material for the synthesis of sodium carboxymethyl cellulose (CMC) by reacting with the cellulose with NaOH and chloroacetic acid at 75 °C for 1.5 h. Effects of alkali dosage, concentration of chloroacetic acid on the physical and chemical properties of the CMC products were investigated. It was revealed that the reactants alkali reagent/chloroacetic acid/cellulose at the molar ratio of 4.6:2.8:1and 4:2.5:1, or at the molar ratio of NaOH/ClCH 2 COOH ≈1.6–1.64, resulted in CMC products of relatively high water solubility. The viscosity-average molecular weight M v of these two CMC products obtained at molar ratios of 4.0:2.5:1 and 4.6:2.8:1 is in the range of 1.94 × 10 4 –2.48 × 10 4 g mol −1 , and the average DS of the two products are 0.57 and 0.85, respectively. As the solute concentration is above 2 wt%, the viscosity of the CMC-water solution exhibits nonlinear (exponential) increasing with increasing the solute concentration (typical of non-Newton fluids).

A method is presented for calculating the electromagnetic forces on the end windings of turbine generators for both the steady state and transient modes of operation. Part 1 of this paper deals with the basic concepts of the force calculation and gives several examples of steady state forces and how they vary with load and power factor. PartII deals with several types of transient operation. The currents and fields which these transients produce are discussed and forces are found for various cases such as short circuits, synchronizing out of phase and transmission line switching.

The article deals with studies of the arcing performance of SF6 puffer breakers at currents of up to 80 kA and voltages of up to 200 kV, using an interrupter unit fitted with viewing windows. The studies are mainly concerned with the behavior of the arc at current zero and with restrike phenomena under various conditions. In addition to measurements of the electrical variables and the pressure variation, the tests cover the use of high-speed cameras, spectroscopic diagnostic methods, and schlieren methods. The density fields and flow fields derived from the latter are used to optimize the gas flow. On the basis of the breaker data and those of its operating mechanism a method for computing the essential variables, e.g., pressure, gas flow, back pressure, and contact travel, is developed. The variation of these parameters as a function of the interrupter data for various currents and with due allowance for the interaction between the arc and the operating mechanism must be known if the breaker design is to be optimized. The method uses simplified equations for the gas flow and the arc. The relationship between the gas data (e. g., density, enthalpy, speed of sound, electrical conductivity, and dielectric strength) and the temperature is taken into account by using approximation functions. The temperature of the arc core is matched to the test results.

The microbial electrolysis desalination and chemical-production cell (MEDCC) is a device to desalinate seawater, and produce acid and alkali. The objective of this study was to enhance the desalination and chemical-production performance of the MEDCC using two types of stack structure. Experiments were conducted with different membrane spacings, numbers of desalination chambers and applied voltages. Results showed that the stack construction in the MEDCC enhanced the desalination and chemical-production rates. The maximal desalination rate of 0.58 ± 0.02 mmol/h, which was 43% higher than that in the MEDCC, was achieved in the four-desalination-chamber MEDCC with the AEM-CEM stack structure and the membrane spacing of 1.5mm. The maximal acid- and alkali-production rates of 0.079 ± 0.006 and 0.13 ± 0.02 mmol/h, which were 46% and 8% higher than that in the MEDCC, respectively, were achieved in the two-desalination-chamber MEDCC with the BPM-AEM-CEM stack structure and the membrane spacing of 3mm.

Abstract Limiting the increase of global temperature requires electrification of the railway transport, which is relatively a distinct mode of transport in terms of economy, business and socialization of a country. However, battery complemented railway transport systems such as fuel cell hybrid railway propulsion systems are constrained by the high cost of the battery, and suboptimal performance of the fuel cell under varying loads. Optimized selection of battery can reduce its costs associated with sizing, life and utilization. Similarly, managing the load distribution between the battery and fuel cell can reduce the load variations concern for fuel cell. In this study, model-based selective characterization of the battery and fuel cell is done to identify the optimal features and constraints. Following characterization, the load allocation to battery and fuel cell is determined with the targets of collaborative utilization of optimal features and mitigation of constraints. Subsequently, considering this load allocation and results of characterization, conditions are proposed for reliable sizing and optimized selection of battery. The significance of the proposed conditions in reliable sizing is explored. Based on these conditions, certain commercially developed batteries are evaluated for optimized selection of battery. The results signify this study as a foundation for research on the reliable sizing and optimized selection of battery in fuel cell hybrid railway propulsion systems.