Artificial Neural Network and Fuzzy Logic Based Techniques for Numerical Modeling and Prediction of Aluminum-5%Magnesium Alloy Doped with REM Neodymium

In this study, the mechanical properties of aluminum-5%magnesium doped with rare earth metal neodymium were evaluated. Fuzzy logic (FL) and artificial neural network (ANN) were used to model the mechanical properties of aluminum-5%magnesium (0-0.9 wt%) neodymium. The single input (SI) to the fuzzy logic and artificial neural network models was the percentage weight of neodymium, while the multiple outputs (MO) were average grain size, ultimate tensile strength, yield strength elongation and hardness. The fuzzy logic-based model showed more accurate prediction than the artificial neutral network-based model in terms of the correlation coefficient values (R).

MECHANISMS INVOLVED IN THE REDUCTION OF INFARCT SIZE BY ACE INHIBITIOR AFTER LEFT CORONARY ARTERY LIGATION IN RATS

The contribution of the inhibition of angiotensin Ⅱ (ANGⅡ) synthesis and bradykinin (BK) breakdown to the effects of ACE inhibition on infarct size, cardiac hypertrophy and blood supply to the marginal zone of the infarcted area

Mechanical size effect of eutectic high entropy alloy:Effect of lamellar orientation

The effect of lamellar orientation on the deformation behavior of eutectic high entropy alloy at the micrometer scale,and the roles of two rarely explored laminate orientations(i.e.,the lamellar orientation at~0°and 45°angles with the loading direction)in regulating size-dependent plasticity were investigated using in-situ micropillar compression tests.The alloy,CoCrFe NiTa_(0.395),consists of alternating layers of Laves and FCC phases.It was found that the yield stress of the 0°pillars scaled inversely with the pillar diameters,in which the underlying deformation mode was observed to transform from pillar kinking or buckling to shear banding as the diameter decreased.In the case of the 450 pillars with diameters ranging from 0.4 to 3μm,there exists a’weakest’diameter of~1μm,at which both constraint effect and dislocation starvation are ineffective.Irrespective of the lamellar orientations,the strain hardening rate decreased with decreasing pillar diameter due to the diminishing dislocation accumulation that originated from the softening nature of large shear bands in the 0°pillars,and the enhanced probability of dislocation annihilation at the increased free surfaces in the 45°pillars.The findings expand and deepen the understanding of the mechanical size effect in small-scale crystalline materials and,in so doing,provide a critical dimension for the development of high-performing materials used for nanoor microelectromechanical systems.

Sintering, thermal stability and mechanical properties of ZrO2-WC composites obtained by pulsed electric current sintering

ZrO2-WC composites exhibit comparable mechanical properties as traditional WC-Co materials, which provides an opportunity to partially replace WC-Co for some applications. In this study, 2 mol.% Y2O3 stabilized ZrO2 composites with 40 vol.% WC were consolidated in the 1150℃-1850℃ range under a pressure of 60 MPa by pulsed electric current sintering （PECS）. The densification behavior, microstructure and phase constitution of the composites were investigated to clarify the role of the sintering temperature on the grain growth, mechanical properties and thermal stability of ZrO2 and WC components. Analysis results indicated that the composites sintered at 1350℃ and 1450℃ exhibited the highest tetragonal ZrO2 phase transformability, maximum toughness, and hardness and an optimal flexural strength. Chemical reaction of ZrO2 and C, originating from the graphite die, was detected in the composite PECS for 20 min at 1850℃ in vacuum.

Effects of Strain Rate,Temperature and Grain Size on the Mechanical Properties and Microstructure Evolutions of Polycrystalline Nickel Nanowires:A Molecular Dynamics Simulation

Through molecular dynamics（MD） simulation, the dependencies of temperature, grain size and strain rate on the mechanical properties were studied. The simulation results demonstrated that the strain rate from 0.05 to 2 ns–1 affected the Young＇s modulus of nickel nanowires slightly, whereas the yield stress increased. The Young＇s modulus decreased approximately linearly; however, the yield stress firstly increased and subsequently dropped as the temperature increased. The Young＇s modulus and yield stress increased as the mean grain size increased from 2.66 to 6.72 nm. Moreover, certain efforts have been made in the microstructure evolution with mechanical properties association under uniaxial tension. Certain phenomena such as the formation of twin structures, which were found in nanowires with larger grain size at higher strain rate and lower temperature, as well as the movement of grain boundaries and dislocation, were detected and discussed in detail. The results demonstrated that the plastic deformation was mainly accommodated by the motion of grain boundaries for smaller grain size. However, for larger grain size, the formations of stacking faults and twins were the main mechanisms of plastic deformation in the polycrystalline nickel nanowire.

Effects of liquid feed rate and impeller rotation speed on heat transfer in a mechanically fluidized reactor

A mechanically fluidized reactor （MFR） is a novel and compact reactor used for biomass pyrolysis. Endothermic biomass pyrolysis requires heat provided from the wall of the MFR. Meanwhile, mixing with a vertical stirrer helps achieve effective heat transfer from the wall to the bed. Here, the heat trans- fer characteristics between the wall of a 1.0-L MFR and its bed of mechanically fluidized sand particles were studied. An induction heating system was used to heat the wall, while a vertical blade stirrer was used for mixing. Heat transfer measurements were carried out using silica sand particles, having three average Sauter mean diameters： 190, 300, and 600 p.m. The overall wall-to-bed heat transfer coeffi- cients were estimated using temperature measurements taken during continuous injection of water onto the fluidized bed. The overall heat transfer coefficient for bed temperatures of 500-700℃ increased as particle size increased or superficial velocity of the vaporized liquid increased. Effect of impeller rotation speed also was investigated. Typically, the overall heat transfer coefficient increased as rotation speed increased. The wall-to-bed heat transfer coefficients obtained in this study are comparable to estimates from traditional bubbling fluidized beds, even at vapor velocities below the minimum fluidization veloccity.