Python app for drawing Bode diagram asymptotes of transfer function for minimum and non-minimal phase systems

The purpose of this article is to introduce an application to draw the asymptotes of Bode diagram module and phase from each constituent elementary factors of any transfer function for minimum and non-minimal phase systems without transport delay. The Bode diagram is the most used tool in the frequency response method. Python was used to program the application to perform the operations as well as the Qt5 Design for the simple graphical interface for the application and all this in the Linux operating system. The application purpose is to assist students in learning the concept and drawing of Bode diagram. For students the non-minimum phase system Bode diagram is more difficult to draw than a minimum phase system due to the presence of zeros and/or poles on right half of s-plane. The phase asymptotes of a quadratic factor was closest to the real phase curve around the corresponding undamped natural frequency and this can be observed in the example showed in this article. This example must be used as a help and not a simply to solve a problem.

Enhanced Mechanical Properties by Ionomeric Complexation in Interpenetrating Network Hydrogels of Hydrolyzed Poly (N-vinyl Formamide) and Polyacrylamide

Tough hydrogels were made by hydrolysis of a neutral interpenetrating network (IPN) of poly (N-vinyl formamide) PNVF and polyacrylamide (PAAm) networks to form an IPN of polyvinylamine (PVAm) and poly (acrylic acid) (PAAc) capable of intermolecular ionic complexation. Single network (SN) PAAm and SN PNVF have similar chemical structures, parameters and physical properties. The hypothesis was that starting with neutral IPN networks of isomeric monomers that hydrolyze to comparable extents under similar conditions would lead to formation of networks with minimal phase separation and maximize potential for charge–charge interactions of the networks. Sequential IPNs of both PNVF/PAAm and PAAm/PNVF were synthesized and were optically transparent, an indication of homogeneity at submicron length scales. Both IPNs were hydrolyzed in base to form PVAm/PAAc and PAAc/PVAm IPNs. These underwent ~5-fold or greater decrease in swelling at intermediate pH values (3–6), consistent with the hypothesis of intermolecular charge complexation, and as hypothesized, the globally neutral, charge-complexed gel states showed substantial increases in failure properties upon compression, including an order of magnitude increases in toughness when compared to their unhydrolyzed states or the swollen states at high or low pH values. There was no loss of mechanical performance upon repeated compression over 95% strain.

RESEARCH OF RELATION OF SAMPLERS FREQUENCY CHARACTERISTICS / STROBAVIMO ĮTAISO DAŽNINIŲ CHARAKTERISTIKŲ SĄRYŠIO TYRIMAS

This paper proposes an algorithm to reduce limitations in band-width measurements of sampling oscilloscopes then using a swept sine-wave measurement method. The traditional swept sine-wave method allow measure only magnitude response. Phase response can be computed only if a sampler is a minimal phase circuit. In this paper alternative bandwidth measurement algorithm using the nose-to-nose method with measurements corrections for the non-idle properties of oscilloscope is de-scribed. Algorithm includes for noise, time base distortions and jitter in measurement signals corrections methods. Proposed algorithm allows to measure phase and magnitude responses when only two similar oscilloscopes and the source of sync pulse are used. Algorithm performs as well as the swept sine-wave method in case when both samplers have the same frequency characteristics. Stroboskopiniai osciloskopai skirti matuoti sparčius periodinius signalus naudojant sąlyginai nesparčius didelio skiltiškumo analoginius-skaitmeninius keitiklius. Vienas iš pagrindinių stroboskopinio osciloskopo mazgų, užtikrinančių, kad osciloskopo charakteristikos atitiktų metrologinius reikalavimus, ir kuriame vyksta matuojamo aukštadažnio signalo spektro transformacija į žemų dažnių sritį, yra strobavimo įtaisas. Šiame darbe pateikiamas strobavimo įtaiso veikimo principas, nagrinėjami įtaiso dažninių charakteristikų matavimo būdai taikant pastovios amplitudės, kintančio dažnio harmoninio virpesio ir priešpriešiais sujungtų strobavimo grandinių metodus. Gauti rezultatai rodo, kad nagrinėjamas strobavimo įtaisas nepriklauso minimalios fazės grandinių klasei ir apskaičiuoti įtaiso dažninę fazės charakteristiką (DFCh) iš dažninės amplitudės charakteristikos (DACh) neįmanoma, tačiau taikant priešpriešiais sujungtų strobavimo grandinių matavimo metodą galima gauti įtaiso DACh ir DFCh nenaudojant papildomos aukštadažnės matavimo įrangos ir mažinant matavimo proceso trukmę.