Advanced Materials Research Vols. 160-162

Abstract: Proper wellbore pressure management is a critical part of the drilling practice, where static and dynamic fluid pressures are used to contain formation pressures and assure wellbore stability, to solve the problem; the anti-flushing device is has been developed. The anti-flushing device is designed to counter downhole pressure increase due to safety of narrow mud window and the key to fast drilling. Reasonable control anti-flushing device is the best way to solve the safety of narrow mud window and the key to fast drilling. This paper describes the anti-flushing device, which is run as an integral part of the drill string. The anti-flushing device has been built to operate the 8-1/2 "section of well drilling, keeping continuous loop, To avoiding annular cutting is sank into accumulation when the drill string were connected and the pump stopped, cleaning the small hole by maximum.

Abstract: In situ composite of Al2O3/GdAlO3(GAP) ceramic eutectic prepared by directional solidification is an interesting candidate for the manufacture of turbine blades because of its excellent mechanical properties. In the present paper, directionally solidified Al2O3/GAP eutectic in situ composite ceramics are manufactured by the laser zone remelting technique to investigate the rapid solidification process. The laser power and scanning rate necessary to carry out the ceramic melt growth is determined. The characteristic microstructure is investigated by scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) and X-ray diffraction (XRD). The as-solidified Al2O3/GAP eutectic presents an elongated colony structure consisting of only -Al2O3 and GAP phases with an oriented growth array. The eutectic spacing is strongly dependent on the laser scanning rate, rapidly decreasing to the sub-micron range for the samples grown at the highest rate. Besides, the formation condition and evolution of the particular microstructure of the composite during rapid solidification are discussed.

Abstract: Molecular imprinted polymer micrcosheres (MIPMs) were prepared through precipitation polymerization by andrographolide using as the template molecule. The morphologies of synthesized MIPMs were characterized by scanning electronmicroscope (SEM). Systematic investigations of the influences of key synthetic conditions, including functional monomers, cross-linkers and porogens, on the morphologies, yields and the recognition properties of the MIPs were conducted. The results indicated that the morphologies of MIPs with DVB as cross-linker was perfect, but their binding affinity is lower than that of MIPs with TRIM or EDMA as cross-linkers. And particle size of MIPs with TRIM as cross-linkers is small but with high binding affinity. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The application of MIPs with high affinity and excellent stereo-selectivity toward andrographolide in solid-phase extraction (SPE) column might offer a novel method for the enrichment and determination of terpenoids compounds in the traditional herbal medicine.

Abstract: Based on the design of specimen with standard hourglass shape, a modified dog-bone-shaped ultrasonic vibrational fatigue specimen was proposed and studied in this paper. The resonance length and the distribution functions of axial displacement and stress of such specimen were obtained analytically. A comparison of the very high cycle fatigue (VHCF) life of 6061 aluminium alloy with dog-bone-shaped specimen and hourglass-shaped specimen was done and it indicate that the forer is obviously lower than the latter and the data obtained by specimen with proposed shape are conservative. Then, the ultrasonic vibrational fatigue test of 6063 aluminium alloy specimen with dog-bone-shape was done, showing that the fatigue failure occured at the middle of the specimen with invariable section where has predicted maximum stress; the S-N curve descends continuously and there is no fatigue limit as the traditional fatigue conception describes; the fatigue crack grows in the form of shearing.

Abstract: Ti coating was deposited on mold steel 3Cr2W8V by PVD and then processed with electron beam surface alloying process. The microstructure, surface roughness and microhardness of electron beam surface alloying treated specimens were investigated by using metallurgical microscope, SEM , XRD, micro hardness tester and roughness tester. It is shown that the electron beam surface alloying treated specimens have a rapidly solidified microstructure consisting of the uniformly distributed TiC phases and fine VCrFe8 intermetallic phases.The coating has a strong metallurgical boning with substrate, and the coating has high hardness, excellent wear resistance. The coating layer has an average microhardness of approximately HV600, 35% higher than the substrate’s. So it is used widely. Furthermore the need for further research is discussed as well.

Abstract: The strength and microstructure characteristics of the nugget in aluminum ally resistance spot welding were evaluated in this study with and without addition of rare earth elements Er, Ce. The strength was assessed using a small punch test mode and the microstructure was studied using an optical microscope, scanning electron microscope, and energy-dispersive spectroscope. Results indicated that the hardness and strength were increased about 10% after adding rare earth elements Er, Ce in the nugget. The grain of nugget zone was refined significantly. In the boundary and interior of the grain, a number of rare elements and its compounds were dispersed. This showed that parts of rare earth elements existed as solid solution in Al Matrix, part as the rare earth compounds. This improved that the elements not only can promote nucleation and refinement, but also can inhibit plastic deformation by hindering the dislocation movement. Thus they could play a strengthened role. The strengthening mechanism of the rare earth elements Er, Ce in the alloy nugget is mainly the second phase strengthening and fine grain strengthening.

Abstract: Nanofluid is a new class of heat transfer fluid which contains suspended metallic or nonmetallic nanoparticles in traditional fluid. In this paper, nanofluids containing low volume concentrations (0.1-0.5vol.%) of Al2O3 and SiO2 nanoparticles were produced using a two-step method with ultrasonication and without any surfactant. Suspension stability of nanofluid was characterized and analyzed using zeta potential, average particle size and absorbancy method. The KD2-pro thermal property meter was used to measure the thermal conductivities of Al2O3(40nm)-water and SiO2(30nm)-water nanofluids at different volume concentrations (0.1-0.5vol.%) and temperature(25-50°C). The results show that adding nanoparticles into base fluid can enhance the thermal conductivity greatly. Furthermore, it is also show that the thermal conductivities increase nearly linearly with the nanoparticle volume concentration increasing, and increase significantly with the temperature increasing. A model of thermal conductivity of nanofluid, which has a much better precision, was proposed. But the values of the model are lower than the measured thermal conductivities.

Abstract: A three-dimensional model is developed to study the dynamic process of three-roll plate bending using finite element method (FEM). In this work, the continuous three-roll bending configuration with cylindrical rolls is used to bend a thick plate into a cylindrical shape. It presents the geometrical setup and the finite element model. This 3D simulation is based on the elastic plastic explicit dynamic FEM under the ANSYS/LS-DYNA environment. Effect of initial strain and change of material properties during deformation is neglected. In order to investigate the influence of parameters on the process, top roller position, friction between rolls and plate, and temperature are also discussed. It is found that the simulation program is a feasible and economical method to study the influence of these parameters, and the FEM simulation can also provide engineers with a convenient analytical tool for optimizing process parameters.

Abstract: Vanadium is an important alloying elements and structural materials, a large part of vanadium was extracted from stone coal. The resources of stone coal are very rich in China. It's an important development direction to extract vanadium in stone coal. The stone coal in Shaanxi Province Shanyang County has been studied. Vanadium was extracted by HDEHP in this experiment, which is in the sulfuric acid solution leaching system. The paper researched the influence of concentration of di(2-ethylhexyl) phosphate (HDEHP), pH, the extraction time, the extraction stages, the phase ratio for the extraction ratio of vanadium, the extraction capacity of organic phase and the extraction isotherm. The best technical parameters: 20% di(2-ethylhexyl) phosphate (HDEHP), TBP 5%, sulfonated kerosene 75%(volume concentration), pH=2.5, phase ratio Vo:Va=1:5 and the extraction time is 5 min, extraction of 5 stages level. The extraction ratio of vanadium is 98.57% from the solution of 2.9658 mg/ml vanadium in that technical parameter. The best stripping of vanadium process parameters: the stripping agent for 1 mol/l of sulfuric acid, phase ratio Vo: Va = 5:1, the stripping time is 5 min, the stripping of three stages. Under this condition we may strip loaded organic phase which contain the vanadium 9.0266 mg/ml, the stripping rate is 99.73%.

Abstract: An ecotype of foamed concrete was prepared from activated fly ash/slag blended cement, a kind of low carbon cement, through physical foaming and hydrothermal curing process. The optimized material proportion and curing conditions were obtained with the aid of orthogonal array technique: activated fly ash/slag blended cement-600 kg and foaming agent-1kg for per cubic meter formed concrete, curing at 60°C for 6 hours. The density and compressive strength of the foamed concrete prepared in this method were 644kg/m3 and 4.5MP respectively, and with lower drying shrinkage and thermal conductivity, good freezing and thawing characteristics.