Physical approach to the analysis of earthed bicommensurate URC networks

The possibility of using a physical approach to the analysis of a special class of commensurate URC networks is considered. The convenience of this approach is proved by applying it to the derivation of Rhodes's conditions.     

Commutated capacitor bank as a filter resonator

The results are given of an experimental investigation into the possibility of using the commutated capacitor bank as a resonator in bandpass filters. Attention is focused on the noise and the crosstalk originating from the time-varying operation of the resonator in connection with a bandpass prototype.     

Prediction of catalyst stability in naphtha reforming

A method to predict catalyst activity (RON) and selectivity (ηc5⁺, liquid yield) of naphtha-reforming catalysts during normal operation is described. It involves performing experiments at normal operational conditions and testing accelerated deactivation. These last experiments have a severe intermediate period at lower pressure. Carbon formation is related to time and the decrease in RON and ηc5⁺ is related to carbon at normal operation. The accelerated deactivation produces a similar coke to the one at normal conditions for an equal amount of coke. Therefore for each time at normal conditions there is a corresponding pressure in the accelerated deactivation test. Power law-equations fit the data well and combining them results in the following relations: P = at^b; Δ_NRON = cP^d; Δ_Nηc5⁺ = eP^f. The coefficients a, b, c, d, e and f depend on the catalyst and are calculated from four or six experiments (half at normal conditions and half accelerated deactivation tests); b, d and f bare negative. The value of pressure for the time at which it is desired to predict catalyst activity and selectivity is calculated from the first equation. This value when applied to the second and third equations gives the activity and selectivity, respectively, that the catalyst will have after time t.     

Voltage-transfer-function synthesis using one negative resistance

This correspondence deals with a method for synthetising a voltage transfer function by means of RLC components and one negative resistance. Any real rational function can be synthetised by means of easy computations, and any value of the load resistance is permitted.     

Note on the sensitivity of a tunnel-diode-amplifier gain to variation of the negative-resistance value

A further contribution to the sensitivity of the gain to the variation of the negative-resistance value of a high-gain single-diode amplifier having a lowpass wideband characteristic is presented. It is proved that the use of a general passive embedding in place of a lossless one does not improve the sensitivity of these amplifiers.