Complex temperature dependence of the dielectric response in simple SmC* phases.

The system under study has a SmA*↔SmC* phase sequence and is described by a basic phenomenological model. However, in contrast to a common approach, changes of the polarisation induced by the external electric field are considered independent of changes of the tilt. As a result, even in the basic model, which does not contain any additional terms usually used to obtain better fits to experimental observations, the frequencies of most of the relaxation modes depend on the temperature non-linearly and their dielectric response is not inversely proportional to the frequency of the mode. The behaviour is a direct consequence of chiral piezoelectric coupling, which influences the polar properties of the relaxation modes depending on the temperature.

The Dangers of Analyzing Thermographic Radiometric Data as Images.

Thermography is probably the most used method of measuring surface temperature by analyzing radiation in the infrared part of the spectrum which accuracy depends on factors such as emissivity and reflected radiation. Contrary to popular belief that thermographic images represent temperature maps, they are actually thermal radiation converted into an image, and if not properly calibrated, they show incorrect temperatures. The objective of this study is to analyze commonly used image processing techniques and their impact on radiometric data in thermography. In particular, the extent to which a thermograph can be considered as an image and how image processing affects radiometric data. Three analyzes are presented in the paper. The first one examines how image processing techniques, such as contrast and brightness, affect physical reality and its representation in thermographic imaging. The second analysis examines the effects of JPEG compression on radiometric data and how degradation of the data varies with the compression parameters. The third analysis aims to determine the optimal resolution increase required to minimize the effects of compression on the radiometric data. The output from an IR camera in CSV format was used for these analyses, and compared to images from the manufacturer's software. The IR camera providing data in JPEG format was used, and the data included thermographic images, visible images, and a matrix of thermal radiation data. The study was verified with a reference blackbody radiation set at 60 °C. The results highlight the dangers of interpreting thermographic images as temperature maps without considering the underlying radiometric data which can be affected by image processing and compression. The paper concludes with the importance of accurate and precise thermographic analysis for reliable temperature measurement.

Chiroclinic effect and the phase diagram of achiral polar molecules in the antiferroelectric smectic B_{2} phase.

The paper presents a detailed analysis of the effects of chiral doping on antiferroelectric B_{2} subphases in bent core systems. The studied system exhibits the phase sequence SmA↔SmAP_{A}↔SmC_{S}P_{A}. The chiral dopant induces the tilt in the SmAP_{A} phase or the tilt modulation in the SmC_{S}P_{A} phase, which is known as the chiroclinic effect, but it also influences the stability ranges and the order of the transition between the phases. The order of the phase transition changes from a continuous for weak effects of chiral doping to discontinuous for strong effects. Competition of interactions results in changes of the phase sequences, which are resumed in the phase diagram. The method that leads to these findings, which could be used for the analysis of other similar systems, is briefly presented as well.