Applied Mechanics and Materials Vol. 151

Abstract: EPDM cable materials were prepared, in which EPDM was used as raw materials, silica as a reinforcement, sulfur and dicumyl peroxide (DCP) as the curing agent, aluminum hydroxide (ATH) and magnesium hydroxide (MH) as the flame retardants. The best content and cure parameters of EPDM cable materials were determined by testing hardness, tensile strength, elongation at break, thermal properties and oxygen index, as well as analyzing SEM. The results showed that the properties of EPDM cable materials with DCP were better than those with sulfur or sulfur / DCP blend. The flame retardance of EPDM cable materials with ATH / MH blend was better than that with ATH or MH. The ideal formula of EPDM flame-resistant cable material was EPDM 100 phr, silica 45 phr, DCP 3.5 phr, ATH 90 phr and MH 10 phr. The best curing conditions were at 170 °C under 1.2 MPa for 10 min.

Abstract: Cellulosic biofuels have been proposed to replace part of traditional liquid transportation fuels. Cellulosic biomass is the feedstock in cellulosic biofuel manufacturing. Costs associated with collection and transportation of cellulosic biomass account for more than 80 percent of the feedstock cost. By processing cellulosic biomass into pellets, density and handling efficiencies of cellulosic feedstock can be improved, resulting in reduction of transportation and handling costs. The pellet temperature is one of the most important parameter in Ultrasonic Vibration (UV-A) pelleting. There is very few literature on the pellet temperature of UV-A pelleting. This paper mainly studied how to on-line measure the pelleting temperature, also, the detailed temperature characteristics of the pellet was obtained. The results are valuable for selecting suitable pelleting parameters and controlling the quality of pellet in UV-A pelleting. Also, the accurate measurement of the pellet temperature is helpful to understand pelleting mechanism, charring, and durability issues.

Abstract: This paper has studied the feasibility of detection of bending deformation on hydrogenation reactor based on magnetic memory test. The bend specimens were made of 2.25Cr1Mo steel, which is always used in hydrogenation reactors. Specimens were divided into defect-free specimen, cracks specimen and welding specimen. And then three-point bending tests were done on the material test machine. The magnetic signals were detected by magnetic memory sensors to research different variation of magnetic signals on different bend stage. The ferromagnetic theory was used to explain the variation. It is feasible to preliminarily evaluate the bend state by the magnetic memory signal.

Abstract: Lifetime prediction of steam turbine components under biaxial thermo-mechanical fatigue (TMF) loading of modern high chromium steel is prerequisite for design optimization. In this paper a phenomenological method which envelopes the synthesis of stress strain hysteresis loops and damage assessment under considering creep fatigue interaction is extended to multiaxial loadings. It is proposed as a post processing step depending on the results of a preceding finite element analysis based on a constitutive material model. Recalculation of biaxial service-type experiments on cruciform specimen of modern high chromium rotor steel 10CrMoWVNbN shows satisfactory results for lifetime estimation.

Abstract: The purpose of this study was to research the effect of tin-nickel alloy plating solution temperature, the dosage of graphite powder on the structure and composition of tin-nickel –graphite composite materials prepared by electrodeposition, discuss the relationship between carbon content and the specific capacity composite plating, charge and discharge efficiency, cyclic reversibility. The results show: control the tin-nickel alloy plating solution at 55-60°C, dosage of graphite powder below 10g.L-1 , [Sn2+]/[Ni2+]=1.7, then by electodeposition, a tin-nickel–graphite composite plating with about 80% of tin content ( mass fraction, similarly hereinafter) and carbon content below 7.82% can be obtained. The SEM shows that the composite plating is consist of small spherical particles forming network structure, with status of porous clusters. The charge/discharge cycle testing and cyclic voltammetry testing of the button cell composed of composite anode and lithium slices indicate: when the carbon content in composite plating increases, the specific capacity, charge/discharge efficiency and cyclic reversibility are obviously increased. When the carbon content reaches to 7.82%, the initial specific capacity is 1034.4mAh•g-1 , after 13 cycles, the specific capacity is 603.4mAh•g-1 , after 50 cycles, the specific capacity is 218.3mAh•g-1. The specific porous structure of composite plating and a good charge/discharge performance of graphite powder improve the electrochemical properties of composite anode materials.

Abstract: Ba_0.5Sr0.5TiO₃ film was successfully fabricated by micro arc oxidation of titanium plate in aqueous solution containing Sr(OH)₂ and Ba(OH)₂ for 25 minutes. X-ray diffraction , energy dispersive spectrometer and scanning electron microscopy were used to characterize the crystalline structure, elements composition and surface morphology and HP4284 capacitance prober was used to analyze the dielectric properties of the film. The micro arc oxidation film is mainly composed of tetragonal Ba_0.5Sr0.5TiO3 phases and possesses both high dielectric constant of 454.2 and low dielectric loss of 0.052 at the frequency of 100Hz.The surface morphology appeares smooth and homogeneous except that some holes are uniformly distributed outwardly.

Abstract: Mullite can be prepared as lightweight refractories for its low thermal conductivity, advanced volume stability at high temperature environment. Using industrial alumina and nature silica powders as starting materials, the mullite aggregates with microporous structure were synthesized by adding some burning-out materials as pore forming agents. The effects of burning-out materials on the pore size distribution, mullite contents and microstructure of microporous mullite have been investigated. The results show that the effects on the mullite contents and microstructure of microporous mullite are significant. All the burning-out materials have a similar effect for the pore size distribution.

Abstract: The reverberation ray matrix method (MRRM) for analyzing dynamic response of elastic trusses is extended and used to solve the natural frequency and vibration mode of laminated beams. In this study, the MRRM is employed to obtain the frequency response function (FRF) of displacement of a laminated beam under the action of a unit impulse load. The natural frequencies are determined from the peak of the curve of FRF when a resonant frequency is approached. And the mode is retrieved from the ad joint matrix of the coefficient matrix of the governing equations of MRRM. The accuracy of result of MRRM is verified by a simply supported symmetrically laminated beam compared with the analytical solution of classical theory, which is also proved by finite element method (FEM).

Abstract: Hollow ZnS microsphere were prepared by hydrothermal method and modified with L-Cysteine. The functionalized hollow ZnS microspheres were characterized using transmission electron microscopy(TEM), field-emission scanning electron microscopy(FESEM), X-ray diffractometer (XRD) and photoluminescence spectroscopy. They were used as fluorescence probes in the determination of ciprofloxacin. The pH value of the system was selected at pH 8.5 with excitation and emission wavelength at 270 nm and 423 nm. Under the optimum conditions, the fluorescence of hollow functionalized ZnS microspheres was enhanced by ciprofloxacin. The responses are linearly proportional to the concentrations of ciprofloxacin, the linear range of calibration curve is 0.20 µg•L-1–870 µg•L-1 for ciprofloxacin, the detection limit is 0.06 µg•L-1.

Abstract: With economic prosperity and social development, various kinds of unconventional concrete structure increases day by day, steel reinforced concrete structure has been widely used. The paper demonstrated the Hefei Yangtze-crossing Campaign Memorial Project, by comparing theoretical results with site monitoring data analysis results, summarized the variation of stress and strain distribution in the cantilever truss steel reinforced concrete beam structure. The main content of this paper introduced the study of steel reinforced concrete with the project to make conclusions that they would be significance to apply in the future similar projects for guidance and reference.