Сonditions of achieving electromagnetic motor maximal efficiency

Energy conversion modes of the electromagnetic motor when the armature is accelerated are established to be preferable with respect to maximal efficiency. A non-saturated electromagnetic motor where the armature is once accelerated in the magnetic field generated by the inductor is considered to be a research subject. New relations are obtained for the analysis of the conditions when the maximal efficiency is achieved with respect to the energy conversion mode and the elementary magnetic cycle configuration. It is shown that the efficiency of about 100 % can be theoretically achieved only if special automatic control means are used. The efficiency cannot be more than a theoretical limit of 50 % if there is no automatic control. The obtained results and conclusions for separate energy conversion modes are well agreed with the results obtained by other authors in the past.

Maximal efficiency of the collisional Penrose process with a spinning particle. II. Collision with a particle on the innermost stable circular orbit

We analyze the collisional Penrose process between a particle on the innermost stable circular orbit (ISCO) orbit around an extreme Kerr black hole and a particle impinging from infinity. We consider both cases with non-spinning and spinning particles. We evaluate the maximal efficiency, $\eta_{\text{max}}=(\text{extracted energy})/(\text{input energy})$, for the elastic collision of two massive particles and for the photoemission process, in which the ISCO particle will escape to infinity after a collision with a massless impinging particle. For non-spinning particles, the maximum efficiency is $\eta_{\text{max}} \approx 2.562$ for the elastic collision and $\eta_{\text{max}} \approx 7$ for the photoemission process. For spinning particles we obtain the maximal efficiency $\eta_{\text{max}} \approx 8.442$ for the elastic collision and $\eta_{\text{max}} \approx 12.54$ for the photoemission process.

Aspects of Optimizing the Magneto Hydrodynamic Naval Thrusters

In this paper, the authors analyze several problems relating to the efficiency of an MHD thruster. In this regard have been defined, calculated and shown by graphs the propulsive efficiency as a function of the magnetic field flux density, used for different thruster sizes. Finally, it was draw the conclusions about the number of necessary thrusters for a maximal efficiency.

Adjustment of observation accuracy harmonisation parameters in optimising the network’s reliability

Appropriate precision and low cost are the basic conditions that have to be fulfilled by a project of a geodetic network. Reliability, translating into the ability to detect gross errors in the observations and higher certainty of the obtained point position, is an important network characteristic. The principal way to provide appropriate network reliability is to acquire a suitably large number of redundant observations. Optimisation of the observation accuracy harmonisation procedure allowing for the acquisition of an appropriate level of reliability through modification of the observation a priori standard deviations is the focus of this study. Parameterisation of the accuracy harmonisation is proposed. Furthermore, the influence of the individual parameter operation on the effectiveness of the harmonisation procedure is tested. Based on the results of the tests an optimal set of harmonisation parameters which guarantees the maximal efficiency of the harmonisation algorithm is proposed.