Optical parameter measurements of a nO.m liquid crystalline compound

Differential scanning calorimetry (DSC) and density studies for a Schiff’s base liquid crystalline nO.m compound N (4 - n - hexyloxybenzylidine) 4´- m - hexylaniline (6O.6) have been carried out. Using the previously reported refractive index data and present density data, the molecular polarizability values for the sample have been obtained. Vuks’ method and Neugebauer’s method have been used to calculate the parallel and perpendicular components of molecular polarizabilities. The calculation of order parameters have been previously done using direct extrapolation method and modified Vuks’ method from the measured refractive indices. The order parameters of the sample have been calculated using the refractive indices and density values following Vuks’ method and Neugebauer’s method. The results obtained have been compared and analysed in detail

Root Canal Anatomy of Maxillary and Mandibular Teeth

It is a common knowledge that a comprehensive understanding of the complexity of the internal anatomy of teeth is imperative to ensure successful root canal treatment. The significance of canal anatomy has been emphasized by studies demonstrating that variations in canal geometry before cleaning, shaping, and obturation procedures had a greater effect on the outcome than the techniques themselves. In recent years, significant technological advances for imaging teeth, such as CBCT and micro-CT, respectively, have been introduced. Their noninvasive nature allows to perform in vivo anatomical studies using large populations to address the influence of several variables such as ethnicity, aging, gender, and others, on the root canal anatomy, as well as to evaluate, quantitatively and/or qualitatively, specific and fine anatomical features of a tooth group. The purpose of this chapter is to summarize the morphological aspects of the root canal anatomy published in the literature of all groups of teeth and illustrate with three-dimensional images acquired from micro-CT technology.info:eu-repo/semantics/publishedVersio

Electric field effect on the blue phase of mixtures of liquid crystalline compounds

Mixtures of cholesteric and nematogenic compounds show Blue phases and also cholesteric phase. Electric field study shows important features and a significant new blue phase in these mixtures. Beautiful optical textures exhibited by these mixtures are reported in this paper

Twist grain boundary phases in the binary mixtures of smectic and cholesteryl compounds

The binary mixture of Terephthal-bis-p-n-hexadecylaniline (TB16A) and cholesteryl nonanoate (CN) exhibits I - N* - TGB(A)- TGB(c*)- Sm A - Sm I - Sm F - Sm. G - K Phases in the concentration region between 95 to 98% of TB 16A at higher temperature range. The 90% of TB 16A exhibits I - N* - TGB(A) - TGB(C) - Sm A - Sin I - Sm F - K phases. The mixtures of concentration between 50 to 80% of TB 16A exhibits I - Sm A - Sm I - K phases. The frustrated blue phase is also observed in the mixtures of lower concentration of TB 16A in CN at higher temperature. Optical, DSC and X-ray studies were carried out for the identification of the different phases. The phase diagram of the Chen-Lubensky model in this context is discussed

Synthesis of a new ferroelectric liquid crystalline compound with ester linkage

A new ferroelectric liquid crystalline compound, 4-(2-butyloxycarbonyl)-Pheny-4-(4-dodecyloxycarbonyl) benzoate (6), has been synthesized by esterification method. The DSC and optical microscopy studies reveals that the compound exhibit ferroelectric and smectic phases at lower and higher temperatures respectively. The NMR & IR spectral studies have also been carried out to verify the ester linkage

Sm A-Sm C tricritical point in TBBA and TBDA mixtures

Terephtal-bis-p-n-decylaniline (TBDA) exhibit a weakly first order Sin A - Sin C Phase Transition Whereas TBBA, a lower homologue of the same series, exhibit a second order Sin A - Sm C transition. In order to investigate the tricritical point (TCP) of Sm A - Sm C transition, a systematic study of binary mixtures of TBBA + TBDA are undertaken. DSC and polarizing thermal microscopy studies infer the TCP of the Sin A - Sin C Transition at the weight percent of 80.05 TBDA in TBBA. We report here a systematic study of the approach of TCP by DSC and density measurements as a function of temperature in few compositions of TBBA + TBDA on both sides of the tricritical point