Automation of perturbation test of taximeter supply voltage

W Głównym Urzędzie Miar wykonuje się badania taksometrów dla potrzeb oceny zgodności tych przyrządów, zgodnie z Dyrektywą MID. W ramach doskonalenia metodyki badań wpływu jakości zasilania taksometru na rejestrowane pomiary zbudowano stanowisko badań wyposażone w program sterujący zasilaczem. Dzięki zastosowanym technologiom informatycznym uzyskano poprawę powtarzalności procesu pomiarowego, obniżono uciążliwość wykonywania badań oraz podniesiono jakość uzyskiwanych wyników, w tym dokładność wykonywanych pomiarów.The tests of taximeters supply voltage perturbations are performed in Central Office of Measures. This tests are part of conformity assessment procedure for taximeters according to MID Directive. For performing tests according to OIML and ISO regulations new measurement system was build. The measurement system contain special software for automation voltage supply characteristic. Automation results in better reproducibility of measurement process parameters, shorter time of measurements and better quality of measurement results

Dielectric and Electrooptic Investigations of B Phases οf Banana-Shaped Thioesters

Electrooptic and dielectric measurements were done for B phases of two banana-shaped homologues 1,3-phenylene bis{4-[(4-nonylo-xy-benzoyl)sulfanyl]benzoate (9OSOR) and 1,3-phenylene bis{4-[(4-dodecylo-xy-benzoyl)sulfanyl]benzoate (12OSOR). Polarizing microscopy allowed to identify $B_{1}$ phase for 9OSOR and $B_{2}$ phase for 12OSOR on the basis of texture observation. Spontaneous polarization measurements were performed using reversal current method. The current response to applied triangular voltage shows that $B_{1}$ phase is a ferroelectric and $B_{2}$ phase - antiferroelectric one for which two well separated peaks were observed. Polarization for phase $B_{1}$ of 9OSOR is rather small and its temperature dependence is unusual for ferroelectric liquid crystals - it increases with temperature. Spontaneous polarization for $B_{2}$ phase of 12OSOR compound is of about 600 nC/$cm^{2}$. Dielectric spectra measured with bias field for $B_{2}$ phase of 12OSOR show two well separated relaxation processes. In the low frequency range the relaxation process is connected with fluctuations of ferroelectric domains. The relaxation process in the high frequency range appearing also without bias field is connected with molecular reorientation. The dielectric spectra measured for $B_{1}$ phase of 9OSOR with and without bias voltage showed only one dielectric relaxation process connected with molecular reorientation around the short axis