A recently developed solid-state joining technique called “friction stir spot welding” (FSSW) is used to combine metal alloys with low weldability. Significant experimental work for this study concentrated on the FSSW of AA6063 and AA5083. The involved fixture setup welding pattern parameters sizes material, all which were done a milling machine. cylindrical shoulder concave (10°) square pin pr...

Many aquatic species in the arid southwestern United States are imperiled, persisting primarily in isolated, low-order streams that are increasingly vulnerable to stochastic disturbances. During 2003 and 2004, we surveyed 39 mountain canyons in southeastern Arizona, USA, for lowland leopard frogs (Rana yavapaiensis), a species that has declined in abundance and distribution across its range in ...

We study the horizon absorption of gravitational waves in coalescing, circularized, nonspinning blackhole binaries. The horizon-absorbed fluxes of a binary with a large mass ratio (q 1⁄4 1000) obtained by numerical perturbative simulations are compared with an analytical, effective-one-body (EOB) resummed expression recently proposed. The perturbative method employs an analytical, linear in the...

The role of recombination during a common-envelope event has been long debated. Many studies have argued that much hydrogen energy, which is radiated in relatively cool and optically-thin layers, might not thermalise the envelope. On other hand, helium contains 30% total occurs deeper stellar We investigate distinct roles played by interaction experienced 12 solar mass red supergiant donor. per...

Modern aeroengine designs strive for peak specific fuel and thermal efficiency. To achieve these goals, engines have more highly loaded compressor stages, thinner aerofoils, blended titanium integrated disks (blisks) to reduce weight. These configurations promote the occurrence of aeroelastic phenomena such as flutter. Two important parameters known influence flutter stability are reduced frequ...