Proposed Wave Momentum Source for Generating the 22-Year Solar Cycle

For the 22-year solar cycle oscillation there is no external time dependent source. A nonlinear oscillation, the solar cycle must be generated internally, and Babcock-Leighton models apply an artificial nonlinear source term that can simulate the observations—which leaves open the question of the actual source mechanism for the solar cycle. Addressing this question, we propose to take guidance from the wave mechanism that generates the 2-year Quasi-biennial Oscillation (QBO) in the Earth atmosphere. Upward propagating gravity waves, eastward and westward, deposit momentum to generate the observed zonal wind oscillation. On the Sun, helioseismology has provided a thorough understanding of the acoustic p-waves, which propagate down into the convective envelope guided by the increasing temperature and related propagation velocity. Near the tachocline with low turbulent viscosity, the waves propagating eastward and westward can produce an axisymmetric 22-year oscillation of the zonal flow velocities that can generate the magnetic solar dynamo. Following the Earth model, waves in opposite directions can generate in the Sun wind and magnetic field oscillations in opposite directions, the proposition of a potential solar cycle mechanism.

WEAR FAILURE MECHANISM AND MULTI-IMPACT PROPERTY OF AUTOMOTIVE ENGINE CHAIN

The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.

Buildings and civil engineering works-Sealants-Determination of changes in cohesion and appearance of elastic weatherproofing sealants after exposure of statically cured specimens to artificial weathering and mechanical cycling

Foreword ISO(the International Organization for Standardization)is a worldwide federation of national standards bodies(ISO member bodies).The work of preparing International Standards is normally carried out through ISO technical committees.Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.

Evaluation on Fatigue Performance and Fracture Mechanism of Laser Welded TWIP Steel Joint Based on Evolution of Microstructure and Micromechanical Properties

The fatigue performance and fracture mechanism of laser welded twinning induced plasticity（TWIP）steel joint were investigated experimentally based on the evolution of microstructure and micromechanical properties.The optical microscopy was used to analyze the evolution of microstructure.The variation of composition and phase structure of fusion zone were detected by energy dispersive X-ray and X-ray diffraction spectrometers.The micromechanical behaviors of the various zones were characterized using nanoindentation.The static tensile test and high cycle fatigue test were performed to evaluate the mechanical properties of welded joint and base metal.The microstructures,tensile properties and fatigue strength of base metal as well as welded metal were analyzed.The fatigue fracture surfaces of base metal and welded joint were observed by means of scanning electron microscopy,in order to identify fatigue crack initiation sites and propagation mechanisms.Moreover,the fatigue fracture characteristics and mechanisms for the laser welded TWIP steel joints were analyzed.

The anelastic origin of mechanical cycling induced rejuvenation in the metallic glass

Mechanical cycling is one of the effective methods to rejuvenate metallic glasses(MGs)and improve their mechanical properties.The anelastic origin of the rejuvenation by mechanical cycling in a La_(30)Ce_(30)Ni_(10)Al_(20)Co_(10) MG was investigated via differential scanning calorimetry(DSC)and dynamic mechanical analysis(DMA).We demonstrate that mechanical cycling promotes the activation of flow defects with short relaxation times,leading to anelastic strains and therefore considerable energy storage,which manifests itself as larger relaxation enthalpy on the DSC curves of MGs.However,the MGs release the excess relaxation enthalpy caused by anelastic strain with time,thus suppressing atomic mobility and elevating β relaxation activation energies.The strategy of mechanical cycling at small strains,as demonstrated in the current work,can expand the energy states of MGs over a wide range of relaxation enthalpies.