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Herein, a new homologues series of fluorinated liquid crystal compounds, In, 4-(((4-fluorophenyl)imino)methyl)-2-methoxyphenyl 4-alkoxybenzoate were synthesized and its mesomorphic properties were investigated both experimentally and theoretically. The synthesized compounds were characterized by elemental analyzer, NMR, and FT-IR spectroscopy to deduce the molecular structures. The differential scanning calorimetry was employed to examine mesophase transitions whereas the polarized optical microscopy was used to identify the mesophases. The obtained results revealed that the purely nematic phase observed in all terminal side chains. All homologues showed to possess monotropic nematic mesophases except the derivative I8 exhibits enantiotropic property. The optimized geometrical structures of the present designed groups have been derived theoretically. The experimental data was explained using density functional theory computations. The estimated values of dipole moment, polarizability, thermal energy, and molecule electrostatic potential demonstrated that the mesophase stability and type could be illustrated. Binary phase diagram was constructed and addressed in terms of the mesomorphic temperature range and obtained polymorphic phases. It was found that incorporation of the terminal F-atom and lateral CH3O group influence both conformation and steric effect in pure and mixed states. The absorption and fluorescence emission spectra of fabricated films were recorded to elucidate the impact of terminal side chain on photophysical properties of synthesized liquid crystal. It was noted that the increase of terminal side chain length lead to reduction of optical band gap, whereas charge carrier lifetime increases.

Resistance of new Ni70Cr21Si0.5B0.5P8C≤0.1Co≤1Fe≤1 and Ni72.65Cr7.3Si6.7B2.15C≤0.06Fe8.2Mo3 glassy alloys to pitting corrosion was studied in 0.25 M sodium nitrate solution, with or without addition of chloride ions, using EIS, CP and EFM techniques.

The incorporation, characterization, and analytical ability of an ascorbic acid (AA) voltammetric sensor, based on the PTH/MWCNTCOOH-RGO/CS/CuO modified carbon paste electrode (CPE), were studied. The nanocomposite was prepared via an in situ chemical polymerization route. The structural characterization, surface morphology, and thermal analysis of the modified polymers were confirmed. The kinetics and mechanism of the oxidation process of AA on the modified electrode were studied via scan rate analysis. The quantitative detection of AA was achieved effectually by a square wave voltammetry (SWV) technique. The proposed voltammetric sensor exhibited high performance in 0.1 M phosphate-buffered solution (PBS) at pH 3. In the pH range 3 to 7 AA undergoes irreversible oxidation via transfer of 2H+/2e-. The proposed sensor showed a wide linear range (5 µM to 2 mM) and a low detection limit (0.613 µM). Additionally, the reproducibility and stability (at the 1 mM level) expressed in terms of relative standard deviation (RSD) was 2.13% and 1.98% respectively. The practicality of the proposed sensor was confirmed by the successful detection of ascorbic acid in fresh orange juice and the recovery was between 107.9% and 92.63%, with excellent accuracy.

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Objectives: The current study aimed to compare the adaptation of the restored class-I cavities with two self-etch adhesives bonded to two resin composite using cross-polarization optical coherence tomography (CP-OCT). Materials and Methods: Cylindrical class-I cavities were prepared on twenty, extracted human premolars. Two self-etch adhesives; Clearfil SE bond 2 (SE; Kuraray Noritake Dental, Japan) and Bond Force (Palfique Bond) adhesive (PL; Tokuyama Dental, Japan) were used in this study that were bonded to either resin composites materials; Herculite XRV microhybrid dental composite (HRV; Kerr, Italy) or Estelite Alpha composite (ESA; Tokuyama Dental, Japan). The specimens were divided into four groups (n=5); SE-HRV, SE-ESA, PL-HRV and PL-ESA. All specimens were varnished and stored in distilled water for 24h. Then, they were submerged in a contrasting medium. After that, all groups were optically imaged under CP-OCT at every 250 µm interval distance. Later, image binarization and gap quantification were carried out using Image analysis software. Result: There was a significant difference between all the groups except between SE-ESA and PL-ESA (p = 0.51). The highest median gap % was seen in PL-HRV group followed by SE-ESA, PL-ESA and SE-HRV. Conclusion: Other than composite filler loading and adhesive formula, the interactions of the adhesive and composite copolymers have great influence on composite adaptation.

Resistivity and passivation behavior of two Ni-base bulk metallic glasses, with the nominal composition of Ni 70 Cr 21 Si 0.5 B 0.5 P 8 C ≤ 0.1Co ≤ 1Fe ≤ 1 (VZ1) and Ni 72.65 Cr 7.3 -Si 6.7 B 2.15 C ≤ 0.06Fe 8.2 Mo 3 (VZ2), in various concentrations of NaOH solutions were studied. The investigations involved cyclic polarization (CP), electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) methods. Cyclic polarization measurements showed spontaneous passivation for both Ni-base glassy alloys at all alkaline concentrations, due to the presence of chromium as an alloying element that formed an oxide film on the alloy surface. The EIS analysis showed that the passive layers grown on the two Ni-base glassy alloy surfaces are formed by a double oxide layer structure. Scanning electron microscope (SEM) examinations of the electrode surface showed Cr, Ni, Fe, and O rich corrosion products that reduced the extent of corrosion damage. Atomic force microscopy (AFM) imaging technique was used to evaluate the topographic and morphologic features of surface layers formed on the surface of the alloys.