Applied Mechanics and Materials Vol. 440

Abstract: The mono-disperse magnetic cross-linked composite micro-spheres containing carboxyl groups have been prepared by an improving method of emulsion polymerization in this paper. Firstly, Fe₃O₄ magnetic nanoparticles were synthesized by co-precipitation, and the Fe₃O₄ magnetic nanoparticles were modified by oleic acid. Secondly, DVB as cross-linker, SDBS as emulsifier and AIBN as initiator, the mono-disperse magnetic cross-linked composite micro-spheres were obtained in aqueous, and consisted of the copolymer of styrene and acrylic acid as shell and the Fe₃O₄ magnetic nanoparticles as core. The magnetic cross-linked micro-spheres would be the rudiment of the magnetic nanonetwork, and be expected to apply a great deal of fields in the future.

Abstract: This paper made two types metal nanoparticles whose laws of motion had bigger different into ethylene glycol became a new type of double metals nanofluids coolant, and through theoretical analysis and experimental observations to research the different of aggregation properties with single metal nanofluids coolant. Research results of theoretical analysis showed that particles motion laws were the important element of nanoparticle aggregation, because of differences in movement, as the same conditions, double metals nanoparticles had the advantage of aggregation number and equivalent diameter of poly group better than single metal nanoparticles. Experimental results showed that through light beam transmittance test, we knew that the transmitting light degree of homogeneity of double metal nanofluids coolant was better than single metal nanofluids coolants; through contrast TME photos, we got nanoparticle aggregation state of three types of metal nanoparticles, and knew the otherness of nanoparticle aggregation state between double metal nanoparticles and Cu nanoparticles and Ag nanoparticles. This paper provides a scientific attempt to solve nanoparticles aggregation.

Abstract: Carbon nanomaterials have generated a tremendous amount of attention in the scientific community. However, little or no attention has been paid to potential uses of carbon nanoparticles as optical properties of carbon nanoparticles in general. In the study reported herein, it shows the functions and properties of aqueous-suspended small carbon nanoparticles with different concentration and size.

Abstract: We demonstrate a combinatorial graphene oxide (GO) and reduced graphene oxide (rGO) thin film sensor fabricated by spin coating and dip casting method. Thermal treatment was followed to convert graphene oxide into reduced graphene oxide at different temperatures. 100ppm of evaporated methanol was utilized to examine the resistance profile of graphene oxide thin film and reduced graphene oxide thin film. Crystalline phase of GO and rGO were characterized by XRD. Surface roughness was observed by FE-SEM. Obvious opposite sensing property of GO and rGO were observed according to drying conditions.It was attributed to the change in number of radicals and type attached to the edge and surface of graphene oxide during reduction. Authors suggest that control of reduction rate by thermal treatment would be the one of the readiest approaches to enhance the selectivity of gas sensing in terms of direction of reaction.

Abstract: In recent years, the carbon fiber is added to more and more sports equipment, and it even becomes major materials for some equipment. Carbon fiber sets off a Black Revolution in the aspect of sports equipment. This article briefly describes the characteristics of the carbon fiber, and analyzes its application in such sports equipment as badminton racket, tennis rackets, fishing rod, ping pong rackets, etc.

Abstract: Thoroughbred horse racetracks consisting of granular composite materials, also referred to as synthetic tracks, were developed for the racing industry with the goal of increasing safety to horses and jockeys and reducing maintenance efforts. These granular composites consist of sand, polymer fiber, and rubber bound together with a high-oil wax binder. The mechanical properties of these surfaces are significantly influenced by material composition, environmental factors, and surface maintenance procedures, and are susceptible to both environmental and mechanical-induced degradation over time. Using a combination of material analytical tests, surface mechanical and chemical properties and changes to them are assessed. Tests used to characterize the surface materials composition include Soxhlet wax extraction, wax oil extraction and sand morphology. Additionally, water-holding capacity, wax differential scanning calorimetry (DSC), gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR), and x-ray fluorescence (XRF) provide insight to the thermal mechanical response of these surfaces as temperature and track composition/conditions change. Pertinent test results for two U.S. synthetic racetracks are included in this work to demonstrate the practicality of using this suite of testing. These tests and results provide a basis for racetrack maintenance decisions with the goal of achieving a more consistent racing surface that should ultimately reduce equine, and by extension jockey, injuries.

Abstract: A comparative study has been made to analyze the impact of interstitial iron in minority carrier lifetime of multicrystalline silicon (mc-Si). It is shown that iron plays a negative role and is considered very detrimental for minority carrier recombination lifetime. The analytical results of this study are aligned with the spatially resolved imaging analysis of iron rich mc-Si.

Abstract: The knowledge of the properties of the coating in terms of wear resistance is of paramount importance in order to prevent the formation of severe damages. In this study, the wear performances of Zirconium oxide (ZrO₂) coating over the surface of electro less nickel plating on aluminum and tool steel substrate is analyzed. The surface morphology of coatings was examined by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) .The wear tests were performed in a pin on disc apparatus as per ASTM G-99 Standard. The coefficient of friction and wear loss are evaluated. The results of the wear test established that coated pins exhibited the lowest average coefficient of friction and the lowest wear loss when compared with uncoated pins.

Abstract: To investigate the stress and strain distribution characteristics of equal channel angular pressing (ECAP), rigid-plastic finite element was used to simulate the aluminum ECAP processing. The simulation results showed that equivalent stress distribution of the sample was uneven, and severe stress concentration was at the channel corner. Equivalent strain distribution of the sample was also uneven, and the deformed sample can be roughly divided as three deformation regions: the front, the middle and the end. At the region of front, the plasctic deformation was extremely uneven and the gradient value of equivalent strain was relatively large, at the region of middle, the plasctic deformation was stable and uniform, at the region of end, there existed material reverse flow the sample contacted with the plunger and bearing heavy three-dimensional compressive stress.

Abstract: The recovery method and process of tungsten, nickel and aluminum from spent catalyst was investigated, which had realized the comprehensive recovery of valuable metals about tungsten, nickel and aluminum. The results showed that leaching rate of WO₃ was above 95% and the recovery was 90.85%, nickel and aluminum leaching rate were 98.27% and 90% respectively, the recovery were 91.83% and 92.78% respectively. It had got the conclusion that the technological process was developed, low-cost, high-extraction and process feasibility with good economic benefits and environmental benefits.