Advanced Materials Research Vols. 887-888

Abstract: In order to reduce the viscosity of crude oil for transport, we often use the way of heating delivery for high pour point, high wax, and high viscosity oil. Crude oil at high temperature, through long-distance transmission, the temperature and pressure changes on the piping stress greater impact. In this paper, in order to explore the main factor of hot oil pipeline stress and the location of key points, we build the XX hot oil pipeline stress analysis model used CAESAR II software, analysis of the impact of changes in temperature and pressure on piping stress when hot oil pipeline running, draw hot oil pipeline stress distribution, clearly identifies the location of key points of stress concentration, and we have come to that temperature is a major factor in generating pipe stress.

Abstract: A series of triaxial compression tests on an artificial ice with strain rate of 1.67×10^-4/s at-6°C are carried out to investigate the mechanical behavior of ice. The influence of confining pressure on deformation and strength characteristics of ice is analyzed based on the experimental results. The results show that the stress-strain behavior and the strength of ice changes with increasing pressure in two distinct phases.

Abstract: The newly proposed rotating bending process of metal tubes is a novel kind of Severe Plastic Deformation (SPD) process, which is expected to refine and control the microstructure of metallic tubular materials. The stress distribution and accumulated equivalent plastic strain of deformation part have a significant influence on the microstructure refinement and control of metal tubes during the rotating bending process. The present study focused on the analysis of stress and strain of deformation part during rotating bending process of metal tubes. The model of the deforming metal tubes was proposed. The formulas for determining the stress and accumulated equivalent plastic strain were successfully achieved by analyzing the deformation of metal tubes during rotating bending process.

Abstract: The artificial panel was prepared by using hemp stem and its characteristics were tested. And the performance of hemp stem-based panel was studied in this paper. Analysis showed that the artificial panel by using hemp stem as material has batter physical - mechanical properties and lower density than routine particleboard and medium density fiberboard; it has good anti - bacterial property and its formaldehyde emission is 0.

Abstract: This paper studied on the influence of impregnation process on original board by using the Styrofan SD 332S which could improve the international bending strength, then own higher wear-resistant, fold-resistant and tear-resistant. Trough single factor experiments, the optimum impregnation processing conditions were: wet cardboard dryness of 45%, immersion at 35 °C for 4 minutes, preliminary drying at 70 °C under the premise of 300 ml, 20% latex concentration, subsequent drying at 100°C for 2h. Under the conditions of impregnation process, the property index of shoes board were: tensile strength 0.34 kN/cm² through immersion 4 h, elongation of 1.56% through immersion 1 h, shrinkage of 0.84% through high temperature drying 1 h, peeling strength between layers 0.29N, fold endurance 5721 times.

Abstract: Considering the combined effects of the magnetic field and viscous dissipation, this paper investigates the problem of two-dimensional incompressible unsteady flow over a horizontal continuous stretching sheet. Due to the strongly nonlinear and various parameters of this problem, the governing boundary layer equations are transformed into a system of nonlinear differential equations through the similarity transformation, and then analytical approximations of solutions are derived by homotopy analysis method. In addition, the effects of physical factors on the flow and heat transfer characteristics are examed and discussed graphically.

Abstract: Welded components of DH36 low alloy high strength steel are widely used in offshore oil platforms and ships building. Stress reliving treatments to these welded components is of great importance. Vibration stress relief (VSR) method is an novel technology to release stress in welded components. In this study, 10×200×1000mm DH 36 steel plates were welded and then treated by VSR for about 1 hour. After the treatment, the residual stress was decreased by 29-72% at the welded toe, where the highest residual stress occurs. The metallographic microstructure of the joint was not changed by VSR. Investigation by transmission electron microscope (TEM) revealed that the amount of dislocations was increased at the welded toe. We hope this study can provide theoretical and practical fundamentals for widespread application of VSR on welded offshore engineering components.

Abstract: Our theoretical study aims to the way of obtain C₃H₄O⁺ fragments laser-induced by Cycloheptanone ion (C₇H₁₂O⁺ ) excited state and gives out a result with proved and directed significance for the corresponding experiments. Using the CIS（Configuration Interaction with Single Substitute） method, calculated Cycloheptanone ion excited state structure and vibrational frequencies.

Abstract: This paper is based on the CO₂ crystal as an example, through the two reasonable simplification ΔH(T,P) ΔH(T) and ΔV(T,P) ΔV(P) into the Clapeyron equation to calculate the melting curve. Because the Clapeyron equation can describe all the first-order phase transition, accordingly it is determining the material T-P diagram provides a new way.

Abstract: The changes of physical and chemical properties of sodium pyroxenite gangue such as decomposition and phase transformation were researched by means of differential thermal analysis and X-ray diffraction. The results show that the natural sodium pyroxenite gangue contains the main mineral of aegirite(NaFe⁺³Si₂O₆), and it contains a number of BaSO₄ and Na₃Ca₂(SO₄)₃F, etc. The water of crystallization decomposes at 554.7°C. The Na₃Ca₂(SO₄)₃F decomposes into the composite sulfate and CaF₂ over a wide range of temperatures. The main mineral of aegirite(NaFe⁺³Si₂O₆) reacts with CaF₂ into NaF gas at 993.4°C. The sodium pyroxenite gangue is melts and releases a small amount of SiF₄ gas in the range of 1193.5-1300.7°C.