Pressure dependence of superconductivity in amorphous Ni x Zr 100-x alloys

Pressure variations of the superconducting transition temperature Ic of a series of amorphous NixZr 1 OO-x alloys have been studied under quasmydrostatic pressures upto 8 G Pa. For amorphous samples having Ni-concentration less than 40%, i)Tc/dP is positive in sign and it decreases non linearly with increase in I. whereasdTcldP is negative in sign for Ni concentration of 45%. Comparison with the Hall coefficient (I) and the thermoelectric power (2) results for the same amorphous alloys leads to the conclusion that s-d hybridization nature of the d-band (Nil plays a central role in the sign reversal behaviour. Application of pressures greater than 2 G Pa to Ni20ZrgO led to the formation of a new phase, w-Zr. which retains its form after the pressure is released.

Two Black Gentlemen Photographed by John Cooper, London/St. Thomas, Ont. [n.d.]

An undated cabinet card of two Black men photographed by John Cooper, who operated as a photographer in London, Ont. and St. Thomas, Ont. from 1857 - 1890. The reverse of the photograph features the photographer's stamp in coloured ink. This photograph was in the possession of Iris Sloman Bell, of St. Catharines. The Sloman - Bell family have relatives who include former Black slaves from the United States. John Cooper is listed as a photographer and daguerrean artist in 1857 - 1890 in London, Ont. and in 1874 in St. Thomas, Ont. Source: Phillips, Glen C. The Ontario photographers list (1851-1900). Sarnia: Iron Gate Publishing Co., 1990. "Cabinet card photographs were first introduced in 1866. They were initially employed for landscapes rather than portraitures. Cabinet cards replaced Carte de visite photographs as the popular mode of photography. Cabinet cards became the standard for photographic portraits in 1870. Cabinet cards experienced their peak in popularity in the 1880's. Cabinet cards were still being produced in the United States until the early 1900's and continued to be produced in Europe even longer. The best way to describe a cabinet card is that it is a thin photograph that is mounted on a card that measures 4 1/4″ by 6 1/2″. Cabinet cards frequently have artistic logos and information on the bottom or the reverse of the card which advertised the photographer or the photography studio's services." Source: http://cabinetcardgallery.wordpress.com/category/cabinet-card-history/