Advanced Materials Research Vols. 217-218

Abstract: The progress of construction projects in the plan are generally based on engineering theory and construction developed on the basis of experience. In addition, The schedule impact on the political and economic situation, resources, technology development and other factors. So progress has a great uncertainty. Once the delay period to the owner and construction unit will be a great deal of risk, so risk control of the progress it is essential. This article describes the uncertainty factors about affect on schedule and progress against these uncertainties should be how to control and progress of risk response.

Abstract: A functional POSS monomer (POSS-NH2) was employed to modify cyanate ester (CE) resin. A series of POSS-NH2/CE hybrids containing different content of POSS have been prepared by melt casting and then curing. The curing kinetics and reaction mechanisms of the resin systems were studied by using FT-IR. The experimental results show that both temperature and POSS content may influence the curing reaction of CE. POSS-NH2 mainly displays the catalytic effect at higher temperature (220oC). While the circumstance is more complex at lower temperature (190oC).

Abstract: A kind of nonfunctional oligomeric silsesquioxane (SSQ), methylsilsesquioxane (Me-SSQ), was used to modify cyanate ester resin (CE) in this paper. First, Me-SSQ was synthesized by the hydrolysis and condensation of methyltriethoxysilane. Then a series of Me-SSQ/CE hybrids containing 0wt%, 1wt%, 5wt%, 10wt% and 20wt% of Me-SSQ were prepared. Curing reactivity of the hybrid materials was studied by differential scanning calorimetry (DSC). Mechanical properties of the Me-SSQ/CE hybrids were studied systematically. Impact strength of the Me-SSQ/CE hybrids reaches its maximum value when Me-SSQ content is 5wt%. However, the flexural strength reaches the maximum value when Me-SSQ content is 1wt%. SEM images accord well with the mechanical properties. It is concluded that appropriate amount of Me-SSQ is favorable to improve the mechanical properties of Me-SSQ/CE hybrid materials.

Abstract: The wollastonite with fibrous structure can be used as the filler in the composite. In this paper, the composite was prepared by incorporating the wollastonite into butadiene styrene rubber (SBR) matrix through the mechanical agitation and roll mixing technologies. Mechanical properties of SBR filled with different amount of wollastonite content were studied and compared. It was shown that the mechanical properties of SBR filled with wollastonite could be improved significantly. The tensile strength and elongation at break were increased with the increase of the wollastonite. The tensile strength could be enhanced from 4.1MPa to 5.0MPa, and the elongation at break from 389% to 572%.

Abstract: The reclaimed rubber was used for many fields, but the mechanical properties especially elongation at break of reclaimed rubber couldn’t meet the requirement due to its recycle property. It was proved that the wollastonite with fibrous structure could improve the mechanical properties in many composite. In this study, the reclaimed rubber modified by wollastonite was prepared by the mechanical agitation and open roll mixing methods. The composite was characterized and tested after the renewed vulcanization, and the mechanical properties could be improved. It was observed from experimental data that the elongation at break could enhance from 238% to 300%. Moreover, the tensile strength could increase to some extent.

Abstract: Epoxynorbornene linseed oil (ENLO) is a new kind of epoxide from renewable sources. An UV-curable organic/inorganic hybrid films using epoxynorbornene linseed oils (ENLO) and surface treated nano-silica were formulated. The mechanical properties，thermal properties and coating properties of the ENLO /silica coatings were evaluated as the function of nano-silica content. The results indicated that after incorporating the nano-silica, the strength, modulus and glass transition temperature of the hybrid films enhanced, while the elongation at break decreased. The nano-silica also improved the hybrid coating properties such as pencil hardness, solvent resistance and surface wetting properties. The morphology observation of the films by atomic force microscopy (AFM) showed that the average silica particle size was ~ 70 nm and the particles were well-dispersed in the organic phase.

Abstract: Based on fiber length, fiber orientation distribution, ratio of length to diameter and fiber-matrix interface, the theoretic prediction equation of tensile strength has been established for glass fiber/thermoplastic polyurethane (GF-TPU) composite. The relationship between the structure and tensile strength of GF-TPU composite was theoretically and experimentally studied. The results showed that the predicted tensile strength fits the test results quite well.

Abstract: Objective: To prepare water-soluble chitosan(WSC) nanoparticles(WSC-NPs) and microspheres(WSC-MPs) , exam the morphology and particle sizes of them and study their effect on lowering lipids . Methods: WSC-NPs and WSC-MPs were prepared by ionic gelation process and spray-drying methods respectively. The effect of WSC-NPs and WSC-MPs on lowering lipids was evaluated by measuring its binding capacities of lipids in the conditions simulating human gastrointestinal tract in vitro. Also, the morphology and particle sizes of WSC-NPs and WSC-MPs were examined under scanning electron microscopy (SEM) and particle sizer. Resluts: WSC-NPs and WSC-MPs were nearly spherical in shape and the mean particles size varied from 200-400 nm and 3-7 μm respectively; The lipids-binding capacities of WSC-NPs and WSC-MPs were more effective compared with water-soluble chiosan. The lipids-binding capacity were enhenced when the particle size were decreased. Conclusion: WSC-NPs and WSC-MPs will be better fat-lowing food additives to replace water-soluble chitosan.

Abstract: The RE/Mn co-doped Co-Zn ferrites were prepared by the ceramic method. Infrared absorption and emission properties were obtained by investigating those ferrites. The IR spectra in the range from 400 to 1200 cm-1 were observed. Mainly, three bands were investigated. The high-frequency bands and low-frequency bands were assigned to the tetrahedral and octahedral complexes, respectively. The intensity of all the bands is found to increase while a decrease in broadness, which is explained on the cation distribution in the tetrahedral and octahedral sites were modified by RE/Mn addition. The Mn substitutes the Fe3+ and enters into the octahedral sites; while the partial RE3+ ions are apt to diffuse to the grain boundaries and others enter into the spinel lattice .This can be explained on the basis of ionic radii and ratios of the substituted cation. The results indicate that IR emissivity seems to be increasing with RE/Mn ratio within 8-14 μm wavebands. The maximum infrared emissivity is 0.968 when La/Mn ratio of 0.20 within 8-14 μm wavebands.

Abstract: According to mechanic properties of steel-lined reinforced concrete penstock, author abstracted and simplified its mechanical model, designed and produced 20 axis tensile structures of reinforced concrete, and proposed the test methods on the ratio of crack widths on two sides of concrete protective covering. The measured results are consistent with the calculation results of empirical formula, which on one hand shows the test scheme is feasible, on the other hand verifies the rationality of empirical formula, and it has important significance for perfecting the theory and application of steel-lined reinforced concrete penstock.