In this research, the photocatalytic degradation of cypermethrin using iron-titanium dioxide (Fe-TiO 2 ) nanoparticles supported in a biomaterial was evaluated. The nanoparticles of TiO 2 were synthesized by the green chemistry method assisted by ultrasound and doped by chemical impregnation using Fe +3 :Ti molar ratios of 0, 0.05, 0.075 and 0.1 to make efficient use of direct sunlight ( λ > 310 nm). All nanoparticles were immobilized on the surface of coconut spathe ( Cocos nucifera ). The degradation was carried out at room temperature and natural pH in a flat plate solar reactor, on which the composite material was subjected. The concentration of cypermethrin was determined after 12,000 J m −2 of accumulated radiation from gas chromatography–mass spectrometry and the resulting material was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, and Brunauer-Emmett-Teller (BET) surface area. The best results were achieved with the use of Evonik TiO 2 P-25, Fe:Ti = 0 and Fe:Ti = 0.05 in suspension, with percentages of degradation of cypermethrin of 99.84%, 99.62%, and 100%, respectively. However, the materials supported on the biomaterial of coconut allowed to reach degradation percentages higher than 80%, with the advantage that it minimizes operating costs, as they are not necessarily filtering or centrifuging processes to separate the catalyst. Keywords cypermethrin , green chemistry , photocatalysis , sunlight , flat plate
The ultrafine tin oxide (SnO 2 ) nanorods/reduced graphene oxide (rGO) composites are synthesized by a two-step hydrothermal method. The prepared nanocomposites are characterized by scanning electron microscope, X-ray diffractometer, and Fourier transform infrared spectra. The results of electrochemical performance show that specific capacitance of the composite can reach 262.2 F g −1 at the current density of 100 mA g −1 in the 1 M Na 2 SO 4 electrolyte. An initial capacitance retention of the composite is 96.1% after 6000 cycles, indicating its excellent electrochemical performance. Keywords supercapacitor , graphene , SnO , , nanocomposites , electrochemical performance
To determine the ballistic limit velocity of titanium–titanium tri-aluminide (Ti/Al 3 Ti)-laminated composites under the action of tungsten alloy spherical fragments, a type of 12.7 mm ballistic gun loading system was used to test the tungsten alloy spherical fragments vertically impacting the Ti/Al 3 Ti-laminated composite targets with different thickness. The relationship between the ballistic limit velocity and the target area density of the Ti/Al 3 Ti-laminated composite was obtained. As the area density increased, the ballistic limit velocity and the ballistic energy absorbed by the target plate also enhanced. Based on the dimensional analysis and similarity theory, a simulation law of tungsten alloy spherical fragments penetrating Ti/Al 3 Ti-laminated composite targets with different thickness was studied and an empirical formula for the ballistic limit velocity was obtained. The research results had an important application value for the optimal design of the light armor protection structure. Keywords laminated composites , ballistic limit velocity , tungsten alloy spherical fragment , penetration
In order to further improve the mechanical properties of Ti-Al 3 Ti laminated composites, the endothermic semisolid reaction was used to fabricate Ti-Al 3 Ti-Al laminated composites, and the quasi-static compressive test, dynamic compressive test, and the ballistic penetration test were conducted on these composites. The results showed that the compressive strength and failure strain of Ti-Al 3 Ti-Al laminated composites prepared at 660°C are 1432 MPa and 35%, respectively. The dynamic response of these composites has obvious strain rate effect, and the crack grows in the shape of “Z.” The V 50 of Ti-Al 3 Ti-Al targets is 509 m s −1 . To sum up, Ti-Al 3 Ti-Al laminated composites have better mechanical properties and anti-penetration properties compared to Ti-Al 3 Ti laminated composites. Keywords laminated composites , sintering temperature , compressive properties , anti-penetration properties , intermetallics
Shape-memory alloy titanium nickel (NiTi) fiber was introduced into continuous ceramic aluminum oxide (Al 2 O 3 ) fiber-reinforced titanium–titanium trialuminide metal–intermetallic laminated (CSMAFR-MIL) composite using vacuum hot pressing (HP) sintering method to improve the microstructure and mechanical properties of the composite. Scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction techniques were employed to characterize the microstructure of the novel CSMAFR-MIL composite. Besides, the tensile tests were carried out on continuous Al 2 O 3 fiber-reinforced Ti-Al metal–intermetallic laminated (CFR-MIL) composite and the CSMAFR-MIL composite to explore the influence of NiTi fiber additive on mechanical behavior of the CFR-MIL composite. The experimental results showed that the intermetallic layer including Al 3 Ti, Al 3 Ti 0.8 V 0.2 , Al 3 Ni intermetallics but without residual NiTi fiber was generated via the reactions of liquid Al with NiTi fiber and Ti foil during preparation. Moreover, owing to the addition of NiTi fiber, intermetallic centerline was prevented effectively to form in the CSMAFR-MIL composite. Moreover, the elemental diffusion occurred between the Al 2 O 3 fiber and the intermetallic, revealing that the metallurgical bonding was formed during the fabrication process. Furthermore, the CSMAFR-MIL composite possessed higher strength and superior ductility than those of CFR-MIL composite attributed to the microstructure optimization. Keywords NiTi fiber , Al , O , fiber , laminated composite , intermetallic , tensile behaviors
