Advanced Materials Research Vol. 1014

Abstract: With advantages including capability of propagation over a significant distance and high sensitivity to abnormalities and inhomogeneity near the wave propagation path, Lamb waves can be energised to disseminate in a structure and any changes in material properties or structural geometry created by a discontinuity, boundary or structural damage can be identified by examining the scattered wave signals. This paper presents an overview of the Lamb-wave-based damage identification in laminated composite plates including the formulation of lamb waves in an isotropic plate.

Abstract: The structure of casting silumins (Al-Si alloys) contains a big share of eutecticum (40-75%) which, as mentioned afore, enhance fluidity and decrease tendency towards formation of clefts and microporosity. Due to this fact the properties of α - phase on one hand as well as quantity, morphology, size, and distribution of eutectic silicium on the other hand are the most significant factors influencing mechanical properties of the casting.

Abstract: The deformation of the bullet non-penetrating the bulletproof helmet can cause a contact between the inside of the helmet and the head. This contact can cause injury to head. In order to study the non-penetrating phenomenon, the material of the bulletproof helmet are regarded as Johnson-Cook material model of ideal plasticity. The helmet surface curve is accurately drew by reference the national standard GA293-2012 "bulletproof police helmet and mask". The research use ABAQUS/Explicit to simulate 54 type pistol with 7.62mm bullet shooting helmet at a speed of 450m per second. The results show that shooting point further away from the top of a helmet, the more damage to head may be cause.

Abstract: Microorganisms to improve oil recovery technology is a comprehensive technology of using beneficial activities and metabolites to enhance oil recovery. The obvious effect of field application and good economic benefits make it be active in the field of oilfield development in the long term. In this paper, through indoor experiments in different concentrations of microorganisms bacteria, different concentrations of nutrient solution and function time, evaluate oil sands de-oiling efficiency. Based on test results, optimize the compound of bacteria that from different sources and find out when the ratio of field and lab bacteria is 1:7, the de-oiling efficiency reach the peak of 86.47%, which further expand the mechanism of microorganisms enhanced oil recovery.

Abstract: The ZnO-SnO₂ nanorods were prepared successfully by wet chemical method and bamboo charcoal as the template. The transmission electron microscope (TEM) results showed that the ZnO-SnO₂ nanorods prepared at 700°C were uniform with the diameters of about 55 nm and the lengths of about 160 nm. The photocatalytic activity was studied while the methylene blue was used as the organic pollutant. The results indicate that the degradation rate of the methylene blue by the ZnO-SnO₂ nanorods was about 89%, twice higher than that of the pure ZnO nanomaterials.

Abstract: Through the thermal simulation test, the curves of austenite recrystallization kinetics is recorded, the influence of the parameters including deformation temperature, strain and strain rate on the austenite recrystallization fraction of Ti microalloyed steels is studied, the recrystallization kinetics equation is calculated, and the austenite recrystallization model of the test steel is obtained. The results improve that Ti inhibits both the dynamic and static austenite recrystallization in high Ti microalloyed steels.

Abstract: Morphologies, particle size distribution, microstructure and hardness of Ni-base self-fluxing alloy Ni60A powders are investigated by means of metallographic observation, laser particle size analysis, Hall flow, infrared absorption, surface rockwell hardness methods. The results indicate that Ni60A alloy powders have better sphericity, more smooth on powders’ surface, less joint structure, and single peak particle distribution similar to normal distribution. Bulk-and needle-like hard metallograph are precipitated in its microstructure and its HRC can reach 60-61.

Abstract: This paper briefly describes the preparation process of SPS composite plate. The compress, buckling and three-point bending tests of SPS composite steel plates are studied. Each test gives the failure mode and stress-strain curve. The results may provide a reference for further research and engineering applications of SPS composite plate.

Abstract: Pore reflects fluid storage capacity of the rock, while the shape and size of the throat, together with the pore throat ratio, control the permeability and fluid reservoir capacity. There are mainly two aspects in microscopic pore structure characteristics evaluation at present: experiment and theoretical modeling. In this paper, several experimental methods and modeling methods that currently exist were compared and analyzed. The analysis shows that in the aspect of experiments, the domestic basic research in the field of three-dimensional pore structure model reconstruction technique is still relatively weak under limited conditions of equipment and technology, while in the aspect of models, the current domestic research is still relatively rare. A conclusion is drawn that the main problems in the study of microscopic pore structure at home are still the degree of improvement in the accuracy of the experiment and the model upgrade.