Advanced Materials Research Vol. 629

Abstract: In the paper, mathematical model of phase change wall prepared by different ways and common wall was built and simulated by ANSYS. Response characteristic of internal surface of phase change material wall on outdoor temperature changes was studied when phase change material was added into the wall by different ways. Results in this paper can provide the basis for the application of the wall with phase change material.

Abstract: Peat usually undergo large secondary settlements depending on the amount of organic content present in the soil. This is because of its special microstructure. The microstructure of peat has interdependence with mechanical and physical characteristics, such as compressive and tensile strength, and water retention. In the present research, peat samples were admixed with different concentrations of cement to enhance its physical, chemical, electrical, and microstructural properties. As a result, the surface electrical of the peat colloids influence the rate of flocculation, and in turn further strength achievement. The results is in contrary with the microstructural analysis that performed by SEM and EDX on the treated peat.

Abstract: The distribution of peat deposits can be found in many countries and peat-land constituents from 5 to 8% of earth land surface, where approximately 60% of the wetlands are peat. An increasing growth of the population leads to the necessity of peat-land utilization for development purposes. This article describes a laboratory study on the effect of sodium silicate on the compressibility parameters of peat, which are settlement, void ratio, compression index and coefficient of secondary compression. The effect of the sodium silicate and ordinary Portland cement on the compressibility parameter of peat is investigated through Rowe Cell consolidation test. At the end of this study, it is shown by increasing sodium silicate (within 2.5%), cement on treated peat, they are able to improve compressibility parameters of fibrous peat much more than conventional binders like pure cement.

Abstract: In order to prepare SCC (self-compacting concrete) which is used as the packing layer in CRTS III type track system this paper primary researched the influence of sand ratio on its performance through experiments of the design of mix proportion. Test results show that when sand ratio is too small, the fluidity of SCC will be bad and the concrete will generate segregation and weeping. If sand ratio is too great, the workability of SCC will not be good either, but segregation will not occur again. The optimum range of sand ratio is 0.56 to 0.58 in this paper, while the range proposed by China Academy of Railway Sciences is 0.50 to 0.55.

Abstract: In order to ascertain the karst development status under tunnel arch, take the appropriate engineering measures according to the different karst state and ensure the tunnel structure safety. Based on the difference electric properties of electromagnetic wave in the different media, for karst development features of large dam tunnel area, applying geological radar, the karst development status under the tunnel arch dam bottom was detected. Geophysical interpretation show the karst of the rock under arch dam bottom develops well and exist karst structure. The tunnel is not safe. In construction, engineering measures such as excavation and backfill are taken. The results show that: the geological radar is a good resolution for karst development situation; the engineering measures adopted are effective.

Abstract: Cement paste with addition of a small amount of (0.9wt%) nano-TiO₂ were prepared. Flexural strength and compressive strength testing results showed that by adding a small amount of nano TiO₂ with good dispersion, the 28-day flexural strength and compressive strength of cement paste modified by nano-TiO₂ was increased by 16.12%, and 14.15%, respectively.

Abstract: In this work, interaction at ambient temperature between silica fume and artificially produced Ca(OH)₂ nanoparticles by two different methods was analyzed. Initial products and formed hydrated phases were characterized by several investigations including X-ray diffraction, thermal analyses, transmission and scanning electron microscopy. Synthesized Ca(OH)₂ nanoparticles appeared regularly shaped and hexagonally plated, with side dimensions from 200nm to less than 20nm. Characterization analyses showed that, by reducing particles dimensions, calcium silicate hydrate phase formation was evident already after 7 day of hydration and a nearly complete consuming of free Ca(OH)₂ after 28 days was observed. Besides, formed hydrate phases showed a highly wrinkled layer with marked crumple and rough-edge surfaces.

Abstract: A Soil Deformation Measurement System using OPENCV library and FFTW library in C++ was developed in this paper. The system applied camera calibration based on neural network and Fasst Fourier Transform (FFT) cross-correlation algorithm for Particle Image Velocimetry (PIV). It is used to obtain soil deformation data, such as displacements, velocity and strain, and visualize the deformation. Experiments show that this system could acquire deformation data from soil images accurately, efficiently and continuously, which provides a strong proof that image processing technology has practical significance and application value in the research field of geotechnical engineering.

Abstract: A third generation kitchen extractor adopting nearby pumping method is investigated by using the computational fluid dynamics software. The numerical results are close to the experiment results, which can be used for supporting the optimum design of the equipment. The important parameters such as the particular distributions of velocity, temperature, and species fraction are obtained, which can supply more information about the pumping mechanism of this equipment. It is concluded that the gas-film-jet-cover technology significantly contributed to guaranteeing the pumping effect. Furthermore, decreasing negative pressure of pumping circle and/or the increasing positive pressure of gas-film-inlet could increase the collection efficiency of the equipment. However, it is necessary to choose the most appropriate pressure for getting enough collection efficiency with relatively low energy cost and working noise.

Abstract: In this paper, the pure rotational dynamic model of one stage gear pair system is developed and the nonlinear factors, such as strong nonlinear suspension, time-varying mesh stiffness, piece-wise backlash and internal error excitation, are included in our model. The relative mesh displacement is employed to convert the semi-define system with rigid displacement model into a define one. Such qualitative and quantitative methods as the bifurcation diagram, Lyapunov exponents, Poincaré section, phase trajectory, power spectrum and time history curve are utilized in present research to illustrate the nonlinear dynamic behavior of the system. The sub-harmonic response, chaotic response and the route to chaos of the system are revealed based on one applicable numerical integration method.