Advanced Materials Research Vol. 904

Abstract: The article examines regularities of high-speed steel surface changes in the phase and structural states of during the electrolytic-plasma processing. It is determined that after modification by electrolytic-plasma influence on the surface of R6M5 high-speed steel formation of small pores, microdefects and fine inclusion. Surface modified layer consists of nitrogen austenite, nitrogen martensite and fine nitride particles.

Abstract: In order to increase the ignition performance and combustion performance of B/PTFE fuel-rich propellant,Li-Al alloy is used to increase the sensitivity of B/PTFE fuel-rich propellant.The impact sensitivity、friction sensitivity、 combustion temperature、 burning rate combustion heat and TGA are tested.The results showed that the sensitivity、combustion heat and ignition performance increase much.The burning rate increased 30~50% and the combustion temperature was relatively stable about 800°C.

Abstract: Fire resistance of structural elements such as columns and beams has been evaluated by the fire test. However, needs of fire design based on analysis using a heat transfer theory and a stress analysis are increasing because the design can reduce not only the period of the fire test but the cost of it. The reliability of the analysis would be totally dependent on the mechanical, thermal databases of their structural steels. This paper evaluates the fire resistance of ordinary grade structural steels manufactured from Korea by examining the mechanical and thermal properties of SS 400, SM 400, and SM 490 at high temperature and comparing them with those defined in Eurocode 3. The results showed that the ordinary structural steel had almost the same characteristics as those in Eurocode 3.

Abstract: The effects of tensile softening curve parameters on the crack propagation P-CMOD and P-CTOD curves were analyzed using a calculation method which adopted the initial fracture toughness as the crack propagation criterion. The results showed that: the whole process of the P-CMOD and P-CTOD curves were affected by the tensile softening curve parameters, especially for the descending segment of the curves, but the peak load and critical crack mouth opening displacement were less affected.

Abstract: Tension stretching process is an important link in production of aluminum alloy thick-plate. Exploring the change of load in tension stretching process is important for the structure designing and key component checking of large-scale tension stretcher. In this paper, the changing law of stretching force in the tension stretching process of aluminum alloy 6063 thick-plate has been investigated by numerical simulation method, and the influence of initial thickness of plate and friction condition in clamping area was analyzed. The results indicated that the initial thickness has a notable influence but friction condition has a little influence on stretching load; and the stretching force increases at first and then decreases slightly, and then it is tending toward stability; and the larger the values of thickness and friction, the more stable the stretching force in the process.

Abstract: A FEM-DEM approach was applied to investigate progressive rupture of concrete structures due to dynamic load including earthquakes. In the proposed method, the finite element method (FEM) designed for modelling stressed and deformed solids has been combined with the motion tracking capability of discrete element method (DEM). A fracture model combining single and smeared crack model is used in our simulation. The FEM-DEM method was used to simulate both the intact concrete behavior and the development of fractures in the indirect tensile test. The simulation results identify the failure mechanisms and validate the nature of tensile crack initiation and propagation in concrete disk. In particular, a comprehensive study on the seismic rupture of the Koyna dam during earthquakes is performed using the proposed method. It is shown that the proposed method can predicate the formation and propagation of cracks in concrete dam due to earthquakes.

Abstract: Objective This study aimed to investigate the Cytotoxic effects of TGFα-SAP on the inhibition of neointimal proliferation after rat common carotid arterial injury. Methods seventy rats were divided into two groups. The TGFα-SAP treated group was treated with local injection of TGFα-SAP (5μg/kg) after injury, and the control group was treated with saline. Rat arterial segment was investigated at 1, 3, 9, and 28 days after operation. Results Compared to the control group, the TGFα-SAP treated group shows a significant inhibition of intimal thickness. Conclusion The results indicated that TGFα-SAP can effectively inhibit neointimal proliferation following arterial injury .

Abstract: Through the analysis on the type of deposition of dirt which is produced from the beer, beverage and dairy production devices. And through the discussion on physicochemical analysis and the principle of cleaning, the test of inorganic dirt cleaning and organic dirt cleaning was conducted. The formula for cleaning was optimized at the same time. From the results of the test, it suggested that it is possible for the single-phase CIP acidic cleaning agent and the developed CIP cleaning process to replace the traditional five-step CIP cleaning process.

Abstract: Transection is one of the most severe injuries in the peripheral nerve. In present study, novel PDLLA/β-TCP conduits for repair of injured sciatic nerve were applied. We firstly introduced the nanoβ-TCP particles into the conduits. The results demonstrated that β-TCP decomposition improved the acid environment from degradation of PDLLA and elevated the local calcium ion content. And the local Ca²⁺ influx promoted the BDNF synthesis and secretion, which is beneficial for the nerve regeneration. All in all, PDLLA/β-TCP composite facilitate the sciatic regeneration through modifying the microenvironment in the conduits.

Abstract: Isothermal compression tests were conducted at various temperature and strain rate combinations over the hot working range (880 to 1040°C and 0.01 to 10.0 s-1) of TC11 alloy. Based on the experimental data, the strain rate sensitivity factors m were calculated. Both the efficiency of power dissipation and the instability parameter were computed, and then processing maps incorporated instability maps were accordingly established at strains of 0.1, 0.3 and 0.6. A method to optimize the forging process of Titanium alloy blisk was proposed based on the processing map. The optimized process of TC11 alloy blisk was achieved using the proposed method and was verified by numerical simulation and experiment. The results showed that this optimal process is applicable to produce blisk with duplex structures.