Synthesis of Flexible Elastomeric Polyurethane Films with High Elasticity and Evaluation of Their Structural Permanency

Flexible elastomeric polyurethane (EPU) films were synthesized by ultraviolet (UV) curing of thermoplastic polyurethanes (TPUs) through the reaction among poly (oxytetramethylene) diol (PTMO), isophorone diisocyanate (IPDI), cis-2-butene-1,4-diol (cis-BDO), and 1,6-hexanediol diacrylate (HDDA). In order to improve elasticity and structural permanency in the synthesized TPUs, cross-linking reaction involving unsaturated groups of chain extender (cis-BDO) and reactive diluent (HDDA) using 27 and 41 seconds of UV radiation is introduced. Investigation of structure and mechanical properties was performed using FTIR, GPC, and tensile tests. Stress-strain behavior showed that Young's moduli of EPUs were in the range of 0.2 to 0.4 MPa, which is evidence for high flexibility. Three times of repeated loading on one sample up to 100% strain with 10 min intervals for its recovery showed that considerable structural change didn't occur under these conditions and all observed permanent sets vanished within a time not exceeding 10 min.     

Parasupersymmetry of Non-Linear and Isotropic Oscillator on Constant Curvature

In this paper we discuss the one-dimensional non-linear harmonic oscillator and isotropic oscillator in positive curvature. We will see that in the special case two different oscillator have a same behavior. Finally, by using the parasupersymmetry algebra we obtain the partner potential and superpotential. These superpotential lead us to obtain the corresponding superchares.     

Synthesis and Characterization of Tin Oxide Nanoparticles by Solid State Chemical Reaction Method

High purity tin oxide nanopowders have been synthesized by using a solid-state chemical reaction technique with annealing at elevated temperature. The effects of two parameters, specifically by controlling the annealing temperature and kind of alkaline chlorides as precursors, the effect on particle size, morphology and IR spectra of synthesized tin oxide nanopowder were investigated. From the X-ray pattern, the crystal structure of the synthesized powders was confirmed as a tetragonal structure. Based on the recorded FTIR spectrum of SnO₂, the IR bands due to SnO₂ vibrations and its lattice modes were observed at 625 and 690 cm⁻¹, respectively. In addition, an important characterization peak has been identified at 1,450 cm⁻¹ due to Sn–O–Sn bridges observed only when LiCl was used as precursor. The formation of Sn–O–Sn bridges was confirmed by TGA–DTA analysis. According to the SEM images, it is obvious to notice that the kind of alkaline chlorides as precursors play a dominant role in controlling the morphology of tin oxide nanopowders.     

A convenient synthesis of some α-oxoketene-N,S- and N,N-acetals

Some α-oxoketene-N,S- and N,N-acetals were selectively synthesized in good to excellent yields by the reaction of 1,1-dimethoxy-4,4-di(methylthio)-3-buten-2-one with primary and secondary amines under moderate conditions. Secondary amines in reaction with α-oxoketene dithioacetal yielded double-substitution products exclusively, whereas primary amines under the same conditions yielded the mono-substituted products as exclusive or main products.     

Study the Role of R2 Term in Cosmological AdS-like Space by AdS/CFT Correspondence

International Journal of Theoretical Physics - It has been shown that AdS/CFT correspondence may be realized between some AdS-like cosmological space and CFT living on the boundary. By extending...     

A dispersive liquid–liquid microextraction based on a task-specific ionic liquid for enrichment of trace quantity of cadmium in water and food samples

In this work, a hydrophilic task-specific ionic liquid (TSIL) of 1-chloroethyl-3-methylimidazolium chloride functionalized with 8-hydroxyquinoline was used in a dispersive liquid–liquid microextraction method followed by flame atomic absorption spectrometry for the enrichment and determination of trace amounts of cadmium (Cd²⁺) ions. The simultaneous chelation and extraction of Cd²⁺ ions was carried out by the TSIL. Fine droplets of the water-immiscible TSIL containing target analyte were generated in situ by addition of an anion exchanger potassium hexafluorophosphate (KPF₆) salt to the sample tube. After phase separation by centrifugation for 4 min, the sedimented TSIL was diluted with acidified ethanol for measurement of Cd²⁺ content. Some significant parameters influence the preconcentration of Cd²⁺ ions such as sample pH, TSIL volume, amount of KPF₆, non-ionic surfactant and salt concentration were investigated. Under the optimal conditions, calibration curve was linear in the range of 5–250 µg L^?1 Cd²⁺ with correlation coefficient of 0.9975 and a detection limit of 0.55 µg L^?1. The relative standard deviation for six replicate measurements of 50 µg L^?1 Cd²⁺ was 1.5%. The method was successfully applied for the extraction and determination of Cd²⁺ ions in water and food samples.     

Determination of zinc in water samples by flame atomic absorption spectrometry after homogeneous liquid-liquid extraction

In this study, a new and simple homogeneous liquid-liquid extraction (HLLE) method based on a pH-independent phase-separation process was developed using a ternary solvent system [water-tetrabutylammonium ion (TBA ⁺)-chloroform] for the preconcentration of Zn²⁺ ions. A Schiff’s base ligand was used as the chelating agent prior to Zn²⁺ ions extraction. Flame atomic absorption spectrophotometry using acetylene-air flame was used for the quantification of analyte after preconcentration. The phase separation occurred due to ion-pair formation of TBA and perchlorate ion. The sedimented phase was then separated using a 100 μL micro-syringe and diluted to 1.0 mL with ethanol. The sample was introduced into the flame by conventional aspiration. After the optimization of complexation and extraction conditions such as pH 9.0, [ligand] = 1.0 × 10⁻⁵ M, [TBA⁺] = 2.0 × 10⁻² M, 100.0 μL of [CHCl₃] and [CLO₄⁻] = 2.0 × 10⁻² M, a preconcentration factor of 100 was achieved for only 10 mL of the sample. The relative standard deviation was 2.3% (n = 10). The limit of detection was sufficiently low and at ppb level. The proposed method was applied to the extraction and determination of Zn²⁺ in natural water samples with satisfactory results.     

The necessary length of carbon nanotubes required to optimize solar cells

Background  

In recent years scientists have been trying both to increase the efficiency of solar cells, whilst at the same time reducing dimensions and costs. Increases in efficiency have been brought about by implanting carbon nanotubes onto the surface of solar cells in order to reduce the reflection of sunrays, as well as through the insertion of polymeric arrays into the intrinsic layer for charge separation.     

Preparation and validation of [67Ga]Ga-phytate kit and Monte Carlo dosimetry: an effort toward developing an impressive lymphoscintigraphy tracer

Journal of Radioanalytical and Nuclear Chemistry - Radiocolloides are essential for the detection of metastatic lymph nodes in breast cancer. In this study [67Ga]Ga-phytate, as an long-lived...