A study of excavated material on the Gagnoa-Guéyo-Bamenadou road project in southwest Côte d’Ivoire was carried out using electrical resistivity tomography with a dipole-dipole configuration. This study aim...A study of excavated material on the Gagnoa-Guéyo-Bamenadou road project in southwest Côte d’Ivoire was carried out using electrical resistivity tomography with a dipole-dipole configuration. This study aimed to determine the nature and volume of the studied cuts. Based on the cumulative distances of the longitudinal sections of the road alignment superimposed on the tomographic profiles, a cumulative volume of 104681 m3 of material was determined. This volume comprises 88557 m3 of soft cuts and 16,124 m3 of rocky cuts, which can be reused in specific embankment zones. This work may, therefore be useful in the characterization of cuts in a preliminary design study, in order to anticipate changes during the road’s development and asphalting.展开更多
Servo scanning 3D micro electrical discharge machining (3D SSMEDM) is a novel and effective method in fabricating complex 3D micro structures with high aspect ratio on conducting materials. In 3D SSMEDM process, the a...Servo scanning 3D micro electrical discharge machining (3D SSMEDM) is a novel and effective method in fabricating complex 3D micro structures with high aspect ratio on conducting materials. In 3D SSMEDM process, the axial wear of tool electrode can be compensated automatically by servo-keeping discharge gap, instead of the traditional methods that depend on experiential models or intermittent compensation. However, the effects of process parameters on 3D SSMEDM have not been reported up until now. In this study, the emphasis is laid on the effects of pulse duration, peak current, machining polarity, track style, track overlap, and scanning velocity on the 3D SSMEDM performances of machining efficiency, processing status, and surface accuracy. A series of experiments were carried out by machining a micro-rectangle cavity (900 μm×600 μm) on doped silicon. The experimental results were obtained as follows. Peak current plays a main role in machining efficiency and surface accuracy. Pulse duration affects obviously the stability of discharge state. The material removal rate of cathode processing is about 3/5 of that of anode processing. Compared with direction-parallel path, contour-parallel path is better in counteracting the lateral wear of tool electrode end. Scanning velocity should be selected moderately to avoid electric arc and short. Track overlap should be slightly less than the radius of tool electrode. In addition, a typical 3D micro structure of eye shape was machined based on the optimized process parameters. These results are beneficial to improve machining stability, accuracy, and efficiency in 3D SSMEDM.展开更多
A solid polymer electrolyte (SPE) films consist-ing of polyethylene oxide (PEO), 50% epoxi-dized natural rubber (ENR50) and LiCF3SO3 with various compositions of PEO-ENR50 and vari-ous weight percentage of LiCF3SO3 we...A solid polymer electrolyte (SPE) films consist-ing of polyethylene oxide (PEO), 50% epoxi-dized natural rubber (ENR50) and LiCF3SO3 with various compositions of PEO-ENR50 and vari-ous weight percentage of LiCF3SO3 were pre-pared by solution casting technique. The poly-mer electrolyte films were characterized using DSC, XRD and AC impedance spectroscopy. The SPE with the PEO-ENR50 composition of 70-30 shows the highest conductivity of 4.2 × 10-5 Scm-1 at the 15 wt.% of LiCF3SO3 compared with the other composition of PEO/ENR50. This composition was then chosen to investigate the effect of LiCF3SO3 on the thermal property, structure and conductivity of the electrolyte. The highest room temperature conductivity of 1.4 × 10-4 Scm-1 was achieved at 20 wt.% of LiCF3SO3. The conductivity result is supported by the DSC and XRD analysis which showed the semi- crystalline nature of PEO turning to amor-phous state due to the increase in LiCF3SO3 content.展开更多
文摘A study of excavated material on the Gagnoa-Guéyo-Bamenadou road project in southwest Côte d’Ivoire was carried out using electrical resistivity tomography with a dipole-dipole configuration. This study aimed to determine the nature and volume of the studied cuts. Based on the cumulative distances of the longitudinal sections of the road alignment superimposed on the tomographic profiles, a cumulative volume of 104681 m3 of material was determined. This volume comprises 88557 m3 of soft cuts and 16,124 m3 of rocky cuts, which can be reused in specific embankment zones. This work may, therefore be useful in the characterization of cuts in a preliminary design study, in order to anticipate changes during the road’s development and asphalting.
基金supported by National Natural Science Foundation of China (Grant No. 50905094)National Hi-tech Research and Development Program of China (863 Program, Grant No. 2009AA044204, Grant No. 2009AA044205)China Postdoctoral Science Foundation (Grant No. 20080440378, Grant No. 200902097)
文摘Servo scanning 3D micro electrical discharge machining (3D SSMEDM) is a novel and effective method in fabricating complex 3D micro structures with high aspect ratio on conducting materials. In 3D SSMEDM process, the axial wear of tool electrode can be compensated automatically by servo-keeping discharge gap, instead of the traditional methods that depend on experiential models or intermittent compensation. However, the effects of process parameters on 3D SSMEDM have not been reported up until now. In this study, the emphasis is laid on the effects of pulse duration, peak current, machining polarity, track style, track overlap, and scanning velocity on the 3D SSMEDM performances of machining efficiency, processing status, and surface accuracy. A series of experiments were carried out by machining a micro-rectangle cavity (900 μm×600 μm) on doped silicon. The experimental results were obtained as follows. Peak current plays a main role in machining efficiency and surface accuracy. Pulse duration affects obviously the stability of discharge state. The material removal rate of cathode processing is about 3/5 of that of anode processing. Compared with direction-parallel path, contour-parallel path is better in counteracting the lateral wear of tool electrode end. Scanning velocity should be selected moderately to avoid electric arc and short. Track overlap should be slightly less than the radius of tool electrode. In addition, a typical 3D micro structure of eye shape was machined based on the optimized process parameters. These results are beneficial to improve machining stability, accuracy, and efficiency in 3D SSMEDM.
文摘A solid polymer electrolyte (SPE) films consist-ing of polyethylene oxide (PEO), 50% epoxi-dized natural rubber (ENR50) and LiCF3SO3 with various compositions of PEO-ENR50 and vari-ous weight percentage of LiCF3SO3 were pre-pared by solution casting technique. The poly-mer electrolyte films were characterized using DSC, XRD and AC impedance spectroscopy. The SPE with the PEO-ENR50 composition of 70-30 shows the highest conductivity of 4.2 × 10-5 Scm-1 at the 15 wt.% of LiCF3SO3 compared with the other composition of PEO/ENR50. This composition was then chosen to investigate the effect of LiCF3SO3 on the thermal property, structure and conductivity of the electrolyte. The highest room temperature conductivity of 1.4 × 10-4 Scm-1 was achieved at 20 wt.% of LiCF3SO3. The conductivity result is supported by the DSC and XRD analysis which showed the semi- crystalline nature of PEO turning to amor-phous state due to the increase in LiCF3SO3 content.
