Applied Mechanics and Materials Vols. 204-208

Abstract: A mide, simple and efficient synthetic procedure for the preparation of 2,7-dibromo-2′,3′,6′,7′-tetra(2-methylbutyloxy)spirobifluorene and key intermediates, tetra(2-methlbutyloxy)biphenyl ，2-bromo-4,5,3′,4′-tetra(2-methylbutyloxy)biphenyl, 2,7-Dibromo-2′,6,3′,7′--tetra(2-methylbutyloxy)biphenyl-9-Fluorenol, has been developed. The procedure described herein offers several advantages, including high product yields, easy purification, and large scale production. Ether protected 2,7-dibromo-9,9′-spirobifluorene has good solubility in organic aolvents to permit an appropriate coating process, ability to achieve various colors so as to make full color display elements possible.

Abstract: In order to study the effects of the application of layer steel fibers and polypropylene fibers on dry-shrinkage properties of concrete, the contrast experiments on the dry-shrinkage ratio and mass-loss ratio of ordinary concrete(OC), layer steel fiber reinforced concrete(LSFRC) and layer hybrid fiber reinforced concrete(LHFRC) under constant temperature (20±2°C) and constant humidity(relative humidity 60±5%) condition were carried out. The dry-shrinkage ratio of LHFRC is smaller obviously than OC’s and LSFRC’s, and achieve a reduction of 26.9%, the dry-shrinkage ratio of LHFRC after adding grinding slag and fly ash achieve a reduction of 40.2% at the age of 180 days. However, the mass-loss of LHFRC is larger than OC’s, and achieve an increment of 18.3% at the age of 180 days, LHFRC after adding grinding slag and fly ash’s is consistent with OC’s. The dry-shrinkage properties of concrete will be improved remarkably by adding layer hybrid fiber.

Abstract: The development of construction materials technology, particularly concrete is growing very rapidly in the presence of nanotechnology. One material that deserves the attention of researchers is nanosilica. Silica has been used on concrete, starting from silica sand as a filler to microsilica (silica fume) as a reactive pozzolan. Based on previous research, silica fume is proven effective to improve the mechanical properties and durability of concrete. A novel nanotechnological process allows producing amorphous nanosilica with high reactivity from locally available silica sand. In this study a locally available nanosilica is used on mortar and concrete thereby limiting the use of commercial nanosilica materials from semiconductor industry waste. To obtain sustainable concrete, the mix is design to have high strength as well as low permeability using as much possible local sources. This study also make use of commercial, regular silica fume combined with the locally produced nanosilica. The results show that combined use of nanosilica with silica fume can increase the compressive strength and durability.

Abstract: A primary study on the resistance to high-temperature-oxidation of 430 ferrite stainless steel and its oxidation process before and after the addition of RE elements was reported. Results show that the oxidation resistance of 430 ferrite stainless steel after adding RE is indeed great. The value of oxidation rate of Sample 1 (without adding RE) is 2.87 times higher than Sample 2, respectively at 1423K after oxidizeing for totally 144h. And the dense and adherent Cr2O3 scale and FeCr2O4 scale are formed and played the protection role to the 430 ferrite stainless steel. In the internal oxidation layer, the pinning effect of silicon dioxide is strengthened by RE.

Abstract: A simple kinetic spectrophotometric method was developed for the determination of trace amounts of Ru (III). The method is based on the reduction of spadns by sodium hypophosphite (NaH2PO2) in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Ru (III) in the range 0.40–10.0 μg/L with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.12 μg/L Ru (III). The relative standard deviation for the determination of 0.10 and 0.20 μg/25mL Ru (III) was 2.3 % and 2.0 %, respectively. The method was applied to the determination of Ru (III) in some ores and metallurgy products.

Abstract: On basis of the residual-stress-field of the composite ceramic, the frictional force on the boundary of the lamellae can be computed. Then the frictional work is determined. The pull-out toughening mechanism is gotten. The result shows that the toughening value is dependent on the size of lamellae: the pull-out toughening value will increase as the thickness of the lamellae increase.

Abstract: A new environmentally friendly polyurethane curing agent was prepared by the method that cyclic carbonate reacted with isophorone diamine. Investigated the synthesis temperature of the curing agent by DSC and FT-IR, and discussed membrane mechanical properties by curing agent and thermal properties of membrane. The results showed cyclic carbonate reacted violently with isophorone diamine in 82 °C, and the carbamate group appeared on molecular chain; breaking strength of the film and given elongation modulus was greatly improved by using this curing agent.

Abstract: In this research, in order to explore the main mechanism of direct and two-stage compression in as-cast light alloy, the mechanical property, microstructure evolution and the flowing of second phase particles were studied, before and after deformation. Then, the influence of the strain volume in first stage on flowing stress of the second stage deformation also was researched.

Abstract: Abstract: Steel fiber reinforced micro-expansive concrete (SREC) with excellent fluidity, high resistance to segregation and good self-compacting ability was prepared. Compressive test, splitting tensile test and flexural test were performed. Self-developed confined expansion test instrument of concrete filled steel tube (CFST) was used to evaluate the deformation behaviors of SREC confined in the steel tube. The structure behavior of steel fiber reinforced micro-expansive concrete filled steel tube (SECFST) was investigated through 12 short column specimens. Expansion agent invariant and steel fiber contents were the dominant variables. The results showed that when compared to common micro-expansive concrete, the splitting tensile and flexural strength of SREC were increased by 78.0% and 64.7%, respectively. When the expansion agent amount was 40kg and volume fraction of steel fiber was less than 1%, SECFST exhibited stable expansive deformation. The use of steel fiber combined with expansion agent moderately improved the yield load and ultimate load of CFST.

Abstract: The blend composite materials of bio-ethanol byproduct-Poly(lactic acid) (PLA) were produced by a twin-screw extrusion process. Effects of bio-ethanol byproduct (BEB) contents and different compatibilizers on properties of composite materials were investigated. The research showed that with the increase of contents of bio-ethanol byproduct, the mechanical properties decreased. The mechanical properties of composites were improved by adding the compatibilizers, especially the polypropylene grafted maleic anhydride (PP-MAH). When the PP-MAH content was 2.5%, the mechanical properties of the composite materials were superior to others.