Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Effect of rare earth cerium addition on the microstructure and tensile properties of hypereutectic Al–20%Si alloy

Effects of rare earth Er additions on microstructure development and mechanical properties of die-cast ADC12 aluminum alloy

https://shell.cas.usf.edu/~phanm/ActaMaterialia-2013-published.pdf

Mechanical and magnetocaloric properties of Gd-based amorphous microwires fabricated by melt-extraction

Eutectic Al–Si–Cu–Fe–Mn alloys with enhanced mechanical properties at room and elevated temperature

Al–Si eutectic alloys with the following composition (wt.%), 13.0 Si, 3.0–5.0 Cu, 0.3–0.8 Fe,  15 (Fe, Mn) 3 Si 2 ) and θ(Al 2 Cu) at the grain boundaries of α-Al dendrites. The ultimate tensile strength (UTS) and elongation of the alloy with 3.0% Cu and 0.3% Fe reach 310 MPa and 3.2%, respectively. By increasing Cu content to 5.0% and Fe to 0.8%, the UTS of Al–Si alloy is further enhanced to 336 MPa. It was observed that these Al–Si alloys fracture in a mixed mode with quasi-cleavage and ductile fracture morphology.

Improved mechanical properties in cast Al–Si alloys by combined alloying of Fe and Cu

In this work, gold nanoparticles (AuNPs) decorated Ti3C2Tx nanosheets (MXene/AuNPs composite) are fabricated through a self-reduction reaction of Ti3C2Tx nanosheets with HAuCl4 aqueous solution. The obtained composite is characterized as AuNPs with the diameter of about 23 nm uniformly dispersing on Ti3C2Tx nanosheets without aggregation. The composite (MXene decorated on 4.8 wt% AuNPs) is further employed to construct supercapacitor for the first time with a higher specific capacitance of 278 F·g−1 at 5 mV·s−1 than that of pure Ti3C2Tx and 95% of cyclic stability after 10,000 cycles. Furthermore, MXene/AuNPs composite symmetric supercapacitor with filter paper as separator and H2SO4 as electrolyte, is assembled. The supercapacitor exhibits a high volumetric energy density of 8.82 Wh·L−1 at a power density of 264.6 W·L−1 and ultrafast-charging/discharging performance. It exhibits as a promising candidate applied in integrated and flexible supercapacitors.

/pdf/in-situ-reduced-mxene-aunps-composite-toward-enhanced-1soka4vz4p.pdf

Enhui Wang

Papers

Eutectic Al–Si–Cu–Fe–Mn alloys with enhanced mechanical properties at room and elevated temperature

Improved mechanical properties in cast Al–Si alloys by combined alloying of Fe and Cu

In situ reduced MXene/AuNPs composite toward enhanced charging/discharging and specific capacitance

Preparation of Zr4+ doped calcium hexaaluminate with improved slag penetration resistance

The effect of nano-γAl2O3 additive on early hydration of calcium aluminate cement