Papers by Keyword: Interaction

Abstract: In this paper, the interference between arbitrary shaped 3D planar crack and cavity existing in the vicinity of the crack front is evaluated. It is assumed that the treated region is unbounded and subjected to uniaxial tension at infinity. The interaction between crack and cavity is treated by body force method. The surface of the crack and cavity is modeled by number of small triangular elements and the density of body force and weight function of the force doublet is assumed at a constant on each triangle. Numerical stress analyses are examined by changing the radius of cavity and the distance between the cavity and crack front systematically. Numerical results are presented for the stresses along the centerline between cavity and crack. To validate the current analysis, numerical results are compared with the results in the literature and found good agreement.

Abstract: By means of analytic function theory, the problems of interaction amongparallel dislocations in one-dimensional hexagonal quasicrystals are investigated. The interaction force of parallel dislocations in the material is obtained in forms of complex variable function firstly, which is the versions of well-known Peach-Koehler formula in one-dimensional hexagonal quasicrystals on parallel dislocations. These results are development of the corresponding parts of quasicrystals. Meanwhile, in this paper, we firstly give the equivalent action point of parallel dislocations in one-dimensional hexagonal quasicrystals, which be of important reference value to researching the interaction problems of many dislocations in fracture mechanics of quasicrystals.

Abstract: This paper presents an analysis of a pile loaded in its head by a horizontal force. The pile crosses subsoil layers of a low bearing capacity and the bearing gravel layer below it. Further an analysis of displacements and internal forces of a bended pile in interaction with the layered subsoil, having various physical properties, is performed.

Abstract: Tin Oxide (SnO₂) thin film is one of the important transparent conducting oxides (TCOs) due to its electrical and optical transparency in visible light spectrum. This study presents the best model in estimating optical properties of tin oxide thin film which is performed using the absorption coefficient of the film. The annealing temperature is at 473 K prepared by radio frequency sputtering technique. Twelve multiple regression (MR) models with interactions are generated from three independent variables (transmission spectra, energy band gap and the wavelength of light). They are developed from data sets of 50. The best model M8.0.0 is chosen from the 6 selected models based on the Eight Selection Criterion (8SC). Best model will have the majority criteria with the least value. Factors affect the absorption coefficient are found to be X₁ (transmission spectra), X₂ (energy band gap) and X₁X₂ (interaction between transmission spectra and energy band gap).

Abstract: Y₂O₃ crucibles have been prepared for as-cast Nb-22Ti-16Si-2Al-2Cr-2Hf and Nb-22Ti-16Si-2Al-2Cr alloys at 1950 °C. The microstructures, metal-crucible interfaces and contaminations were evaluated. Experimental results demonstrated that a mild interface reaction occurred between the Y₂O₃ crucibles and Hf, resulting in some inclusions dispersed in the metallic matrix. However, without Hf addition, no apparent reaction layers or inclusions were found. Both alloys were slightly contaminated with oxygen as the result of slow thermal dissociation of Y₂O₃, and its extent depended on Hf contents and holding times.

Abstract: In order to improve the bearing behavior and the bearing capacity of single pipe pile, the technology of step cross-section pipe-pile is proposed.Based on FLAC3D, the finite difference model of the pile-soil interaction established,bearing behaviors of step cross-section pipe pile and unimate cross-section pipe pile is studied comparatively and bearing performance influence factors of step cross-section pipe pile is discussed.The results show that the bearing capacity of step cross-section pipe pile is much higher than unimate cross-section pipe pile in the same geological conditions and material dosage. For layered foundation, the bearing capacity of single pile may be improved by setting variable cross-section pile joint in relatively hard soil. But the depth of joint embedded in hard soil has little influence on bearing capacity of single pile.There is an obvious effect on increasing capacity of single pile by improving soil properties of soft soil surrounding pile.

Abstract: The thermal distortion of friction pair will be produced in high line speed frictioning. For solving interaction theory from this problem, thermal distortion micro-bulges model of two interaction friction surfaces is built by ways of micro-interaction dynamics, and equations of contact forces of micro-bulges are obtained. By using mathematic statistics and normalization, equations of macro-normal and tangential contact forces are obtained, and relation between friction coefficient and micro-parameters is found. Contact forces and friction coefficient characteristics expressed by parameters of dimensionless clearance and curvature are simulated. The results show that the interaction theory is important in deeper understanding friction and wear theory in high line speed running, and offers reliable proof for future finer structure design of friction pair and model design of clutch.

Abstract: Two reversible trypsin inhibitors, Kunitz trypsin inhibitor (KTI) and Bowman-Birk trypsin inhibitor (BBI) were compared to find the more optimal one as the inhibit factor during trypsin immobilization. Fluorescence spectroscopy, UV–visible absorption spectroscopy and circular dichroism (CD) spectroscopy were used to explore the effects of the two inhibitors on trypsin in activity and structure. The results showed that both inhibitors combined with trypsin in 1:1. CD circular dichroism spectroscopy showed that KTI and BBI led to different changes in trypsin second structure. The results can help us find out the mechanism between the two inhibitors and trypsin and select the more optimal inhibitor in trypsin immobilization.

Abstract: This paper investigates the dynamic properties of each sub-system of a coupled railway train-bridge interaction system. Both spatial beam-plate model and spatial grillage model are built for a long-span dual-deck cable-stayed railway bridge by use of finite element method. The railway train is modeled as a mass-spring-damper system. Then free vibration equations are established based on the finite element models and then subspace iteration method is employed to calculate the dynamic properties for each sub-system. Results show that the spatial grillage model agrees well with the spatial beam-plate model in terms of mass and stiffness distribution. The spatial beam-plate model serves as benchmark solution and the grillage model as a tool for dynamic responses of the coupled system due to its computational efficiency. It also shows that first modes of both the railway train and long-span bridge are lateral direction, which indicates that the train may experience much response in lateral direction. Therefore attention should be drawn to the lateral running stability and safety of railway train due to the coupling effect between the bridge and railway train.

Abstract: The incorporation of fly ash (FA) in cementitious matrices have been frequently used in order to make the matrix more resistant to the action of chlorides. On the other hand, it is known that Ca (OH)₂ existing in the matrix is partially consumed by the pozzolanic reactions, which facilitates the advancement of carbonation. Given that the combined action between carbonation and chloride penetration is a fact little known, we speculate about the behaviour of the matrix in this context. This study investigates the influence of the presence of chlorides on the carbonation in mortars with FA. Samples with 0% and 40% replacement of cement CEM I 42.5 R for FA were molded with water/binder 0.56 and 0.52 respectively. After 90 days of curing the specimens were subjected to cycles of immersion/drying for 56 days. Half of the samples was subjected to the following cycle: two days in a solution containing NaCl (concentration equal to 3.5 %); 12 days in the carbonation chamber (4% of CO₂). The other half was: two days in water; 12 days in the carbonation chamber. Then, the development of carbonation was evaluated. The results indicate that the presence of chlorides influences the carbonation. The specimens submitted to the exclusive action of CO₂ showed a greater depth of carbonation compared to that presented by the specimens subjected to combined action. This may be related to changes in properties of the matrix which may lead to further refinement of the pores and related to the presence of the salt that can lead to partial filling of the pores and the increase in moisture content .