Abstract We detail the design of a variable energy, x-ray fluorescence source using low activity (1.8×10 6 dpm) 99 Tc β that irradiates thin foils. By rotating among foils Ti, Zn, Nb, Ag, and Au, device produces x rays between 4 70 keV at rate near 1 Hz. When is placed in storage position, external radiation non-detectable. The shielding rotation mechanism permits use vacuum liquid nitrogen tem...

this paper tries to systematically survey, with taking theoretical view on geomorphic basin and its changes into account. the purpose of this research is to determine the balance and stability of geomorphic basins from the past to present and then to future. consequently, it tries to determine the balance between energy and input-output materials for example (rainfall , solar radiation, tectoni...

Nanoparticles of nickel substituted cobalt ferrite (Nix Co1-xFe2 O4 : 0£ X£ 1) have been synthesized by co-precipitation method. Triton x-100 and oleic acid as surfactants were used. Particles size as estimated by the full width half maximum (FWHM) of the strongest X-ray diffraction (XRD) peak were found 17 and 21nm. Their morphology structure have been determined by scanning electron microscop...

introduction: the present study evaluated the element distribution in completely set calcium-enriched mixture (cem) cement after application of 35% carbamide peroxide, 40% hydrogen peroxide and sodium perborate as commercial bleaching agents using an energy-dispersive x-ray microanalysis (edx) system. the surface structure was also observed using the scanning electron microscope (sem). methods ...

background: the purpose of this study was to evaluate long-term changes in bone density profile among survivors of childhood acute lymphoblastic leukemia. patients and methods: this was a 5 year prospective study comprised of thirty-one survivors of childhood acute lymphoblastic leukemia with a mean age of 11.8 (4.6) years, who completed therapy at least 1 year previously (according to the all-...

sio2-coated cobalt ferrite (cofe2o4) nanoparticles were obtained by the hydrolysis of tetraethylorthosilicate in the presence of cofe2o4 nanoparticles in co-precipitation. the effects of sio2coating on the magnetic properties of cofe2o4 nanoparticles were investigated. the structural, morphological and magnetic properties of as-prepared sample were characterization by x-ray diffraction (xrd), f...

The project "Energy and Society," sponsored by the Swedish Secretariat for Futures Studies, has studied different indigenous energy sources as alternatives to imported oil in Sweden. One alternative is nuclear energy, antoer is renewable energy. Large uncertainties are associated with both alternatives today. The main characteristics of an energy policy for the rest of the century that does not...