Evaluation of the mechanical characteristics of hygrothermally aged 2-D basalt-aramid/epoxy hybrid interply composites

Polymer composites used in outdoor applications are exposed to environmental factors such as temperature and moisture which may affect the mechanical performance of the composites. In this study, the influence of moisture absorption on the mechanical properties of basalt-aramid/epoxy hybrid interply composites were evaluated. Two different types hybrid interply composites were taken for the investigation namely (301 A/03 B/301 A) and (451 A/03B/451 A). Composites were prepared using compression molding process and cut specimens were subjected to three different ageing environments for 180 days. Selected ageing conditions are, (i) ambient temperature ageing (ii) Sub-zero temperature ageing (−10°C) and (iii) Humid temperature ageing (40°C and 60% Relative humidity). Mechanical tests of the aged composites were carried out to analyse the behaviour of the composites. Moisture uptake of the specimens follow Fick’s law of diffusion with saturation absorption of 5.44%, 3.12% and 1.80% for ambient, sub-zero and humid specimens respectively. Results revealed that (301 a/03 B/301 a) aged composites possess higher mechanical properties compared to (451 a/03 B/451 a) aged composites. Highest reduction in properties were observed in ambient aged specimens followed by humid and sub-zero specimens. Scanning electron microscopy (SEM) was employed to observe the damage modes of the fractured specimens. Matrix deterioration, micro cracks and fibre fracture were the major types of failures observed in aged laminates.

Influence of Preparation Method on the Structural, Linear and Nonlinear Optical Properties of TiN Nanoparticles

In this paper, titanium nitride nanoparticles were prepared in three methods, In the first method, titanium nitride nanoparticles were prepared by the Ball-mill method; in the second and third methods, the nanoparticles were synthesized by the sol-gel, and the co-precipitation methods. The samples were characterized by X-ray diffraction (XRD), UV-Vis spectroscopy, and scanning electron microscopy (SEM), for the study of structural, linear optical properties, and surface morphology study, respectively. The Z-scan technique was utilized to study the TiN nanoparticles nonlinearity. A change in nonlinear optical behavior with an increase in input pump power and concentration of the TiN nanoparticles was observed. Results showed that the TiN nanoparticles give new potentials in nonlinear optical applications. The nonlinear optical behavior of the TiN nanoparticles shifts from inverse saturation absorption to saturation absorption with increase of intensity.

Quantum-sized silicon for enhanced photoluminescence and optical nonlinearity

Si quantum dots (SiQDs) with intrinsic characteristics demonstrate significantly enhanced photoluminescence (PL) and nonlinear saturation absorption (NSA) performances.

Application of saturation absorption spectroscopy to study the hyperfine structure of 235U and accurate 235U/238U isotope ratio determinations at 861.031 nm

The uranium transition 5f36d7s2 (5L6) → 5f37s27p (5K5) at 861.031 nm was studied using saturation absorption spectroscopy. The hyperfine structure of the 235U isotope was determined by measuring the Doppler-suppressed...

SOME ASPECTS OF THE MATERIALS’ OPTICAL LIMITING FEATURES

Due to the effective use of the fullerenes and other nanoparticles in the materials for the general optoelectronic, laser and display technique, as well as for biomedicine, the different mechanisms to attenuate the light intensity are considered with good advantage in order to protect the human eyes and technical devises from high laser irradiation. Reverse saturation absorption, complex formation, scattering, etc. are taken into account. In the current paper the influence of the content of the nanoobjects on the interface relief is shown and considered as an additional possible optical limiting mechanism. Moreover, the diffraction from the nanostructured materials via high frequency Kerr effect is added to extend the numbers of the optical limiting mechanisms. Different experimental instruments and supporting models are presented. VIS lasers, AFM, OCA devises are applied to test and visualize the results. Theoretical and experimental data are in good coincidence.

Nonlinear Optical Properties of Materials Based on Graphene Oxide: A Review

Background: Nonlinear optical properties of Graphene and Graphene Oxide have been widely used in industry and academia. Graphene oxide disperses easily in water and has easier interaction with other materials because of the presence of oxygen groups. So, this feature of Graphene oxide enables us to manipulate its nonlinear optical properties by combining it with other nanoparticles. Objective: We introduced recent advances in the nonlinear optical properties of materials based on Graphene oxide. Methods: Nonlinear optical properties and optical limiting of Graphene oxide and/or its composites with various nanoparticles, considering the wavelength and the incident pulse width, are investigated in this review. Conclusion: At low intensities and in all pulse regimes, saturation absorption seems to be the dominant mechanism of nonlinear absorption in Graphene oxide, while at higher intensities, the main mechanism is the reverse saturation absorption. In the regime of very short pulses of picoseconds and femtoseconds, the dominant mechanisms of two-photon and multiphoton absorption lead to reverse saturation. In the nanosecond pulse regime, long laser pulses and short pulses with high pulse repetition rates, excited-state absorption and nonlinear scattering due to thermal effects are causing the nonlinear process.

Effect of a Small Amount of Iron Impurity in Sphalerite on Xanthate Adsorption and Flotation Behavior

Through industrial testing at the Huize lead-zinc mine, it was found that the floatability of sphalerite varied greatly with the iron impurity content. Three kinds of Huize sphalerites with iron contents of 2.30 wt.%, 3.20 wt.% and 4.66 wt.%, were used to study the influence of small amounts of iron impurity in the sphalerite on xanthate adsorption and flotation behavior. The flotation experiments showed that the flotation recovery increased with the increase in iron impurity content. Fourier Transform infrared spectroscopy (FTIR) and Ultraviolet–visible (UV-VIS) spectra showed that the adsorbed products of xanthate on the surface of three kinds of sphalerite were metal xanthate. The adsorption capacity measurements showed that the saturation absorption of xanthate on sphalerite increased with the increase in iron impurity content. The cyclic voltammetry curve and Tafel curve showed that with the increase in iron impurity content, sphalerite was more easily oxidized and the adsorption rate of xanthate on the surface of sphalerite increased obviously. To summarize, a small amount of iron impurity was beneficial to the recovery of sphalerite.