Synthesis and Properties of High Tilted Antiferroelectric Esters with Partially Fluorinated Alkoxyalkoxy Terminal Chains

Novel chiral esters with partially fluorinated alkoxyalkoxy terminal chains are described. Their phase transition temperatures, enthalpies, and electrooptical properties are reported. A helical pitch in pure compounds and their mixtures based on selective reflection of light is also characterized

Synthesis And Mesomorphic Properties Fluoro- And Chloro - Substituted Isothiocyanatotolanes

We report the synthesis procedures, phase transition temperatures, optical and dielectric properties of the fluoro and chloro - substituted two rings and three rings isothiocyanatotolanes. Three eutectic mixtures comprising of these isothiocyanatotolane compounds showing a wide nematic range, low viscosity and high birefringence (∼0.4) are formulated

Physical Properties Of Laterally Fluorinated Isothiocyanato Phenyl-Tolane Liquid Crystals

We have designed, synthesised and evaluated the physical properties of some high-birefringence (Δn) isothiocyanato phenyl-tolane liquid crystals. These compounds exhibit Δn ∼ 0.48-0.52 at room temperature and wavelength λ = 633nm. Laterally substituted fluorine atoms eliminate smectic phases and lower the melting temperature. The moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. © 2008 Taylor & Francis

Concept of high mobility wheelchair with hydrostatic drive system

W artykule omówiona została koncepcja wózka inwalidzkiego wysokiej mobilności z hydrostatycznym układem napędowym. Przedstawiono istniejące rozwiązania wózków napędzanych ręcznie lub z zewnętrznego źródła energii. Zaproponowano oryginalne rozwiązania układu napędowego, zawieszenia oraz skrętu niespotykane w wózkach inwalidzkich. Przeprowadzono analizę wymaganych podzespołów oraz analizę ich rozmieszczenia. Na tej podstawie stworzono model dynamiczny poddany badaniom określającym komfort kierowcy oraz obciążenia konstrukcji. Przeprowadzono analizę wytrzymałościową zaproponowanej konstrukcji. W rezultacie powstała innowacyjna koncepcja wózka inwalidzkiego wysokiej mobilności zdolnego do przemieszczania się w warunkach w których mogą poruszać się ludzie.The article presents the concept of a high mobility wheelchair with a hydrostatic drive system .It presents existing solutions of manually driven wheelchair and external powered solutions. It was proposed original drive system, suspension system and turning system unheard in wheel-chairs. It was analyzed the distribution of required components. On this basis there was created dynamic model. It was subjected to tests determining the driver's comfort and the load on the structure. The strength analysis of the proposed structure was carried out. As the result, it was created an innovative concept of the high mobility wheelchair capable to moving everywhere where other people can do

Control algorithm of a precision seeder

This paper addresses the issue of the control system of a precision seeder. This seeder is to be used to dispose seeds in one field in such way that the plants originated from those seeds resemble the pixels of a digital image, thus acting as a "garden printer". The seeder is developed to be used for seeding public gardens with complex images and shapes, but the knowledge obtained on its development is to be used as well in other fields of precision agriculture. After a brief description of the components of the seeder, the control algorithm will be presented, as well as the mathematical principles behind it. At the end of this document a field test, where the logo of the Industrial Institute of Agricultural Engineering was seeded/"printed" on the snow (in order to be visible), is shown

Molecular Engineering Of High Birefringence Liquid Crystals

Several linearly conjugated isothiocyanato (NCS) tolanes, biphenyl-tolanes and bistolanes were synthesized and their properties evaluated. Eutectic mixtures compromising these compounds were formulated. The temperature dependent birefringence, visco-elastic coefficient and figure-of-merit were measured. These isothiocyanato tolane mixtures exhibit a favorably high figure of merit at elevated temperatures. Potential applications of these mixtures for laser beam steering, tunable-focus lens and telecom variable optical attenuator are emphasized