Advanced Materials Research Vols. 1030-1032

Abstract: Energy harvesters of PVDF can be used to power small electrical loads or wireless sensor systems. Simple technologies are sufficient for the fabrication of these harvesting modules. Critical process step is the polarization of the piezoelectric material. Main piezoelectric parameters depend strongly on the polarization material. Particularly, the electric field strength and the polarization temperature influence the remanent polarization of PVDF. Dielectric breakdowns of the film at higher temperatures prevent a sufficient polarization. At least, all modules were polarized at a field strength of 100 – 120 MV/m and a temperature of 90°C.Modules with dimensions of 165mm x 95mm x 1.5mm were used to power a commercial available “development kit for Energy Harvesting Wireless systems” (EnOcean ‘EDK 300’). The modules possess of 20 layers of PVDF. Each module was connected via a standard four diode full rectifier bridge with the development kit EDK 300. Positioned underneath a parquet floor (thickness=10mm), the modules converted mechanical energy of footsteps into electricity. Goal of these investigations were to find out configurations suited to generate a sufficient energy level to supply the operation of the EDK 300. Two capacitors in the development kit are used to start the operation of the kit (C₁=470μF) and to store converted energy (C₂=0.25F). Already a few steps onto one module were sufficient to charge C₁ and to start the operation of the EDK 300. Following steps (>100) produced energy which was stored in C₂.

Abstract: In a high-temperature environment, the pyrolytic reaction of the SiC fiber destroyed the chain structure of the fiber and cause fiber apparent weightlessness, the surface and internal of fiber produce porous structure defects. In order to improve high-temperature thermal stability of SiC fiber that the reunion composite powder (CP) of perlite and nanozirconia was prepared by atomized granulation technology, and the CP is sprayed the surface of SiC fiber by plasma spraying technology. The SiC fiber was completely ablation at 1200°C for 3h. On the contrary, the spraying CP of fiber is not affected, showing favorable high-temperature stability. The surface appearance of the fiber was analyzed by means of SEM, and the flame temperature Spray Watch.

Abstract: Using the PCM/B3LYP method with the 6-31+G(d,p) basis set by Gaussian 09, the configuration of 4,4'-dihydroxydiphenyl ether in water was optimized, then the distribution of electrostatic potential, frontier molecule orbital (energy gap for transition) and reactivity descriptors were obtained by calculation and graphical analysis to analyze the activity and reactivity of 4,4'-dihydroxydiphenyl ether in water environment. The results have shown that: the 4,4'-dihydroxydiphenyl ether is found to be useful to both bond electrophilic and electrophobic group in water, especially the electrophilic ones; the energy gap for first-level transition of 4,4'-dihydroxy diphenyl ether is 0.36117 a.u, reflecting the low reactivity relatively.

Abstract: In order to achieve function-structure integration and improve mechanical properties and energy absorption capability of the foam aluminum composite,foam aluminum filled with silicone rubber-modified epoxy resin was prepared.Static compression test shows that the platform yield stage of foam aluminum filled with modified epoxy resin is uplifted,the mechanical properties and energy absorption capability of foam aluminum are improved.The results are helpful to expand the application of aluminum foam.

Abstract: In this paper, the difference of core-mode effective refractive indices (RIs) and the long-period fiber grating (LPFG) resonant wavelength in an uniaxial-crystal fiber resulted from two fiber analysis models were demonstrated and analyzed. The two models are two-layered medium model which is normally used for conventional single-mode optical communications fiber and three-layered medium model. Using Transfer Matrix Method (TMM) based on Coupled-Mode Theory (CMT), the different dispersion properties of chirped long-period fiber gratings (CLPFG) calculated by both models were compared. The result shows that the difference of the core-mode effective RIs is significant especially when the cladding radius and cladding mode order are small, which indicates the limitation of the two-layer model, and that reducing the cladding radius and increasing the cladding mode order can improve the CLPFG dispersion compensation capability effectively. This paper provides guidance to the design and accurate analysis of CLPFG based dispersion compensator (DC).

Abstract: Each of the fuels distributed on the market must meet the quality requirements of the relevant standard. Some change of the methods and limits were also lonked to the addition of the biofuels in motor fuels. This article is focused on the determination of the distillation curve of gasoline blended with biobutanol as a possible alternative to bioethanol. It also defines the basic terms such as distillation, boiling and distillation curve parameters simultaneously. The experiment is aimed at comparing the distillation curve of pure gasoline and mixed fuel containing 5% and 10% biobutanol and for comparison and 5% and 10% ethanol. Furthermore the analyzed distillation curve of gasoline containing 30%, 50%, 85% biobutanol was also compared to that of net biobutanol and gasoline. The use of bioethanol is facing a number of problems. Developments in the field of biofuels is directed to the use of the second generation, which are made from non-food agricultural production and waste biomass. Biobutanol is now classified as such biofuels.

Abstract: The chromatographic analysis of gas dissolved in oil can monitor transformer operation state at any time.It will help to find out transformer latent fault.The chromatogram analysis of locomotive transformer oil mainly adopts the improved three-ratio method.This paper introduces the improved three-ratio method and chromatogram analysis steps,through the concrete example,shows that the improved three-ratio method for transformer fault diagnosis result is basically matched with the actual fault reason,and summarizes attentions.

Abstract: TiC-TiB₂/ Fe matrix composite coatings were in-situ synthesized in the surface of Q235 steel substrate by TIG/cored-wire weld overlaying. The microstructure, micro-hardness and wear resistance of the weld overlay coating were investigated using SEM, XRD, Micro-hardness Tester and Pin-disc Wear Tester respectively. The results showed that the weld overlay coating presented a dense microstructure with defect-free of pore and crack, and better metallurgical bond with the substrate; TiC and TiB₂ particulate distributed dispersively in Fe matrix of the weld overlay coatings. The highest Micro-hardness of the weld overlaying was 1657.58HV, which is 6 times higher than the substrate, and wear resistance are also improved at the room temperature under normal atmosphere conditions.

Abstract: the one pass compression test of Mid-Ti Contained in Q345B was achieved by using the Gleeble-1500 thermal simulation experiment machine. The true stress-strain curve was studied under the deformation temperature was between 1000 to 1150°C and the strain rate was from 0.01 to 0.3 s^-1. And then, based on Sellars model, the function relationships between critical strain (ε_c), strain rate (ε) and deformation temperature (T) of dynamic recrystallization of the Mid-Ti Contained in Q345B were reached: ε_c=2.588×10^-3Z^0.12, Z=εexp (439583/8.314T).