To realize a structure which can be conveniently tuned to multiple and wideband frequency ranges, a geometrical-stiffening membrane acoustic metamaterial (MAM) with individually tunable multiple frequencies is presented. The MAM is realized by a stacked arrangement of two membrane-magnet elements, each of which has a membrane with a small piece of steel attached in the centre. It can be tuned individually by adjusting the position of its compact magnet. The normal incidence sound transmission loss of the MAM is investigated in detail by measurements in an impedance tube. The test sample results demonstrate that this structure can easily achieve a transmission loss with two peaks which can be shifted individually in a wide low-frequency range. A theoretical consideration is analysed, the analysis shows that the magnetic effect related to this distance leads to a nonlinear attractive force and, consequently, nonlinear geometrical stiffening in each membrane-magnet element, which allows the peaks to be shifted. A reasonable design can make the structure have a good application prospect for low-frequency noise insulation where there is a need to adjust the transmission loss according to the spectrum of the noise source.

In nuclear facilities, the reading of the sensors is very important in the assessments of the system state. The existence of an abnormal state could be caused by a failure in the sensor itself instead of a failure in the system. So, being unable to identify the main cause of the “abnormal state” and take proper actions may end in unnecessary shutdown for the nuclear facility that may have expensive economic consequences. That is why, it is extremely important for a supervision and control system to identify the case where the failure in the sensor is the main cause for the existence of an abnormal state. In this paper, a system based on a wireless sensor network is proposed to monitor the radiation levels around and inside a nuclear facility. A new approach for validating the sensor readings is proposed and investigated using the Castalia simulator.

The measurement of SO2, and fluorine compounds concentrations in the air at 8 points on the King George Island, South Shetland Islands, were done in January and February 1979. The received values were similar to the ones for regions recognized as the world background areas. The activity of the Polish Antarctic Station did not influence the air pollution status neither in its surroundings, nor in penguins colonies and extinct volcano areas on Penguin Island.

Artykuł przedstawia możliwe drogi rozwoju procesów decyzyjnych w pojazdach autonomicznych. Najwyższy stopień autonomiczności oznacza, że to nie kierowca, ale system (maszyna, sztuczna inteligencja) podejmuje decyzje o czynnościach na drodze. Całkowita autonomiczność pojazdów zapewnia przewidywalność, ogranicza ilość wypadków, ale też wiąże się z koniecznością wypracowania systemów etycznych, do których w sytuacjach kryzysowych sztuczna inteligencja będzie mogła się odwołać. Oczywiste jest, że nie można przewidzieć wszystkich sytuacji, które zaistnieją na drogach, dlatego konieczne jest stworzenie praw robotowo-ludzkich, które będą nowym i obowiązującym wszystkich dekalogiem. Kluczowa jest kwestia tego, by prawa robotowo-ludzkie były powszechne, transparentne i rzeczywiście odnosiły się do wszystkich podmiotów; w innym układzie na drogach będzie panował chaos, a prognozowany spadek ilości wypadków, zamierzony dzięki wprowadzeniu pojazdów autonomicznych, nie dojdzie do skutku.