Applied Mechanics and Materials Vols. 121-126

Abstract: This paper presents a novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, and a micro-grinding experiment is carried out to study micro grinding principle of the fabricated tools. The manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surface quality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaft grinding tool, the roughness accomplished in the experiment is about 0.086μm.

Abstract: This study analyzed the characteristics of bridge scoured by clear water according to 14 groups of laboratory experiments. The formulation of critical velocity based on historical equations of clear water scour was concluded for the test circumstances in laboratory. The experimental conditions include the variation of flow velocity, sediment cover depth, and diameter of bridge pier/bases. The erosion status prior to the maximum scour depth was recorded by a pinhole camera, and, in general, the equilibrium scour depth was reached after 24 hours. The maximum scour depth increases as the sand cover depth decreases. As the same sediment depth, the fast flow velocity will induce the deep scour depth with respect to the slow flow velocity. The same result can be observed for the large diameter of pier (or base) versus the small one. The maximum scour depths in the front of the pier are always deeper than that behind the pier.

Abstract: By adopting heat-stew steel slag(HSSS) as a contrast, this research studied the gas quenching steel slag(GQSS) grindability using fractal theory and grinding power index. The results showed that the two kinds of steel slag had a good fractal characteristic, and the smaller fractal dimension was, the better grindability would be. Studied on the fractal dimension and grinding time of the two kinds of steel slag as well as their specific surface areas, a conclusion drawn that with the extending of grinding time, the fractal dimension of them would be continuously increased. However, within the same grinding time, GQSS not only have a relevant good distributed particle structural and a smaller fractal dimension, but also have a better linear relation between specific surface areas and fractal dimension. By determining the grinding power index, the correctness of using fractal theory to study GQSS can be proved. Meanwhile, the result also shows that GQSS has a better grindability.

Abstract: Plate shape NaZnPO4·H2O was synthesized by solid-state reaction at low temperature and characterized by X-Ray Diffraction, Scanning electron microscope and elemental analysis. Thermochemical study was performed with an isoperibol solution calorimeter. Based on Hess’s law, thermochemical cycl was designed to determine the dissolution enthalpies of reactants and products using a solution-reaction isoperibol calorimeter at 298.15 K, and the molar reaction enthalpy was calculated on the basis of above dissolution enthalpies. The results show that the obtained product is plate shape NaZnPO4·H2O. The standard molar formation enthalpy of the NaZnPO4·H2O is ΔfHm [NaZnPO4·H2O,s]= -1967.18 ± 0.69 kJ•mol-1.

Abstract: Glass fibers feature extremely low thermal conductivity, high modulus, high toughness, light weight and non-combustible property. These materials can work in situations in which plastics and metals would fail and need to be part of designer’s repertoire. They have many applications in design engineering and can solve many special problems. This paper contains a number of chapters as follows: introduction to glass fibers, manufacturing processes of glass fibers, markets and applications of glass fibers. The conclusion of this paper contains some strategic lines of glass fibers usage in industry and estimations about the future development of glass fibers.

Abstract: At the present work are considered the peculiarity of highly alloyed Aluminum cast iron Al22D crystallization, its casting, mechanical, exploitation and thermal properties, and also presented the examples of produce of castings from it.

Abstract: In this paper, a kind of Magnetic Shape Memory Alloy (MSMA) model based on hysteretic nonlinear theory was developed. Von del Pol nonlinear difference item was introduced to interpret the hysteresis phenomenon of strain-magnetic field intensity (MFI) curve of MSMA. The final relationship among strain, stress and magnetic field intensity was obtained in partial least-square regression method to describe the variation of strain-MFI curve with stress. The result of forecast test shows that the model can describe the characteristics of MSMA in different stress well. The new MSMA model is easy to be analyzed in theory, which is helpful to application of MSMA in engineering fields.

Abstract: Soils at many existing and former industrial areas and disposal sites are contaminated by petroleum hydrocarbons. In this study, laboratory bench-scale experiments were performed to evaluate the effectiveness of applying in situ chemical oxidation (ISCO) on the treatment of petroleum-hydrocarbon contaminated soils. Three different oxidation processes including Fenton’s oxidation, persulfate oxidation, and permanganate oxidation were evaluated with initial total petroleum hydrocarbon (TPH) concentration of approximately 3,920 mg/kg. The major control factors were oxidant species (hydrogen peroxide, persulfate, permanganate) and soil to liquid volume ratios (1 to 3). The oxidant concentration was 5 wt.%. Ferrous iron was used as the catalyst during the Fenton’s oxidation and persulfate oxidation processes, and the oxidant to ferrous iron molar ratio was 1 to 0.1. Among these three oxidation processes, contaminated soils treated by permanganate oxidation had the highest TPH removal efficiency (94% of TPH removal) during 360 min of operation. Approximately 75 and 61% of TPH removal was observed in batch experiments applying Fenton’s oxidation and persulfate oxidation, respectively. Due to the consumption of ferrous iron (used as the catalytic chemical) in the early stage during the operational period, both persulfate and Fenton’s oxidation processes had less TPH removal efficiencies. Frequent supplement of catalyst is required when persulfate and Fenton’s oxidation is applied for field application. Results from this study indicate that the ISCO scheme is a feasible technology for the treatment of petroleum-hydrocarbon contaminated soils within a short treatment period. The experimental results can be used for a scale-up system for practical application.

Abstract: The edge of material loss is crucial for material loss evaluation. Lamb wave tomography and model-based edge detecting have been used in isotropic media. Time of flight and velocity of lamb wave are ultrasonic signal features to reconstruct the edge map of material loss. The correlation technique is employed to get the time of arrival more accurate. An ellipse model is used to represent the defects with apparent directional property, and edge detecting will be realized by it. The reconstructed map shows clearly that edge detecting method in this paper is efficient for material loss detection.

Abstract: With the rapid development of wind power industry and the increasing tension of land resources, WTGS(Wind turbine generating set) changes from Onshore wind machine to offshore wind machine. Because the offshore wind turbine works in the complex environment, it is a higher challenge for tower security. This paper focuses on the load analysis of 2.5MW wind turbine tower, in which a segment solution is applied. Wind load is solved in the superior segment of tower. In the lower segment, the coupling factor of wind and wave is taken into account. Irregular waves are simulated on the basis of the linear wave theory, and then wave load is derived. Accordingly, loads on the tower are calculated by using MATLAB software, and the load spectrum of every node is drawn, which lays a foundation for the dynamic response analysis and fatigue life analysis of tower.