Science a weekly journal, is published each Friday by the American Association for the Advancement of Science at Mt. Royal & Guilford Avenues, Baltimore 2, Maryland. Founded in 1880, it has been sinee 1900 the official publication of the AAAS. Editorial, Advertising, and Circulation Offices, 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Telephone, EXecutive 6080 or 6061. Cable address SC...

The attenuation of high pressure shock waves has been investigated. High purity copper, 6061-T6 aluminum, 6A1-4V and a phase titanium, an uranium alloy and two alloys of beryllium were examined experimentally at pressures as high as 3 megabars. Low pressure experiments were instrumented with a velocity laser interferometer. Intermediate pressures (to several hundred kilobars) were instrumented ...

The ESS-Bilbao facility, hosted by the University of the Basque Country (UPV/EHU), envisages the operation of a high-current proton accelerator delivering beams with energies up to 50 MeV. The timeaveraged proton current will be 2.25 mA, delivered by 1.5 ms proton pulses with a repetition rate of 20 Hz. This beam will feed a neutron source based upon the Be (p,n) reaction, which will enable the...

Vacuum brazing products have excellent joining quality, less deformation and fewer residual stresses. The vacuum brazing technique has significant effect on the microstructure and property of the aluminum brazed joint, but there is little discussion about the optimization of the process. This study investigates how different process parameters affect the tensile properties of 6061-T6 aluminum v...

The present work demonstrates that friction stir welding (FSW) is a feasible route for joining 6061 aluminium (Al) alloy to AISI 1018 steel. The weld has a good weld quality and is free of cracks and porosity. The tensile failure happened at the boundary between the nugget and thermomechanically affected zone of the base Al alloy, indicating that the weld has a higher joining strength. Despite ...

A new digital-based model is presented for the prediction cutting forces in 3-axis CNC milling of surfaces. The model uses an algorithm to detect the work-piece/cutter intersection domain automatically for given cutter location (CL), cutter and work-piece geometries. The algorithm uses a voxelization framework to voxelize the cutter helix as well as the work-piece and based on voxel intersectio...

Measurements of microwave attenuation at room temperature and 4.2 K have been performed on some conductors commonly used in receiver input circuits. The reduction in loss on cooling is substantial, particularly for copper and plated gold, both of which showed a factor of 3 loss reduction. Copper passivated with benzotriazole shows the same loss as without passivation. The residual resistivity r...