The synthesis and properties of a few dozen highly evolved analogues of (S)-MHPOBC are reported. The liquid crystal phases, and phase transition temperatures and enthalpies, as evidenced by polarized optical microscopy and differential scanning calorimetry, respectively, are given. The helical pitch in pure compounds and some mixtures is estimated using the selective reflection method. All of the compounds show antiferroelectric phases, and some key structure–property relationships for the new materials are reported. Specifically, it is found that the length of the oligomethylene segment of a novel partially fluorinated alkoxy ether tail incorporated into the structures strongly influences the stability of the antiferroelectric phase and the observed phase sequences, as well as the values of the helical pitch and its temperature dependence. The formulation of a family of broad temperature range eutectic mixtures possessing the highly desirable orthoconic antiferroelectric phases with long helical pitch is described.

In search of the long-pitch orthoconic antiferroelectric liquid crystalline mixture 1–3 D’have, K , Rudquist, P and Lagerwall, ST . 2000. Solution of the dark state problem in antiferroelectric liquid crystal displays. Appl. Phys. Lett., 76: 3528–3530. Dąbrowski, R , Gąsowska, J and Otón, JM . 2004. High tilted antiferroelectric liquid crystalline materials. Displays, 25: 9–19. Piecek, W , Perkowski, P and Raszewski, Z . 2010. Long pitch orthoconic antiferroelectric mixture for display applications. Mol. Cryst. Liq. Cryst., 525 (in press) with a broad antiferroelectric smectic phase was successfully formulated. The effect of additive of structurally non-compatible antiferroelectric dopant 4 Hamplova, V , Bubnov, A and Kaspar, M . 2003. New ferroelectric and antiferroelectric liquid crystalline materials containing differing numbers of lactate units. Liq. Cryst., 30: 627–631. [Taylor & Francis Online], [Web of Science ®] [Google Scholar] on the phase structure, transition temperatures, and electrooptical properties of an antiferroelectric orthoconic mixture W1000 3 Piecek, W , Perkowski, P and Raszewski, Z . 2010. Long pitch orthoconic antiferroelectric mixture for display applications. Mol. Cryst. Liq. Cryst., 525 (in press) [Google Scholar] was investigated with thermal, electro-optical, and XRD methods. Experimental data demonstrates that eutectic mixture W1000F obtained by doping of mixture W1000 with highly tilted antiferroelectric dopant maintains the orthoconic properties. The effects of the significant reduction of the rotational viscosity of the admixture is presented and discussed. Comprehensive analysis of parent mixture W1000 and doped mixture W1000F revealed that the affects the intralayer as well as interlayer intermolecular interactions.

In this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of the layer was characterized using the scanning electron microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS). It was found that aluminide coating improve the high temperature fatigue performance of MAR247 nickel based superalloy at 900 °C significantly. The coated MAR 247 nickel based superalloy was characterized by the stress amplitude response ranging from 350 MPa to 520 MPa, which is twice as large as that for the uncoated alloy.

The aim of our research was the preparation of a family of 4'-(ω-perfluoroalkanoyloxy)alkoxybiphenyl-4-yl (S)-4-(1-methylheptyloxy)benzoates smectic liquid crystals. The synthesis has been designed in search of new compounds with a high-tilted smectic C* phase. Five homologous series of chiral esters have been obtained. Phase transition temperatures and enthalpies for all compounds, as well as tilt angle, spontaneous polarisation, helical pitch and layer thickness for some, have been measured. The shapes of the molecules were also simulated. Relationships between the chemical structure and the observed physical and chemical properties are discussed. Unexpectedly, the compounds show a low-tilt smectic C* phase, and sometimes also a smectic C*_A phase; an explanation of this feature is given.

The objective of this study was to compare three methods for determining the Young’s modulus of polylactic acid (PLA) and acrylonitrile-butadiene-styrene (ABS) samples. The samples were manufactured viathe fused filament fabrication/fused deposition modeling (FFF/FDM) 3D printing technique. Samples for analysis were obtained at processing temperatures of 180 °C to 230 °C. Measurements were performed with the use of two nondestructive techniques: the impulse excitation technique (IET) and the ultrasonic (US) method. The results were compared with values obtained in static tensile tests (STT), which ranged from 2.06 ± 0.03 to 2.15 ± 0.05 GPa. Similar changes in Young’s modulus were observed in response to the processing temperatures of the compared methods. The values generated by the US method were closer to the results of the STT, but still diverged considerably, and the error exceeded 10% in all cases. Based on the present findings, it might be concluded that the results of destructive and nondestructive tests differ by approximately 1 GPa.

Four racemic compounds (R, S)-4′-(1-methylheptyloxycarbonyl)biphenyl-4-yl 4-[3-(2,2,3,3,4,4,4-heptafluorobutoxy)prop-1-oxy]benzoates were synthesized and characterized. Their mesomorphic properties, such as phase transitions temperatures and enthalpies were measured by polarizing optical microscope and differential scanning calorimetry. The example of mixture containing racemic components and its properties is presented.