The distribution of some heavy metals, namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic sediments of Igbede, Ojo and Ojora rivers of Lagos was studied weekly in the early summer (November) of 2003. The levels of selected trace metals were determined using Atomic Absorption Spectrophotometer (UNICAM 969 AAS SOLAR). Trends in heavy metal burdens in the sediments revealed weekly variations in all...

A large thin film sample of FexCr1−x alloy with a composition gradient x=0.38−0.52 has been prepared by co-sputtering to investigate magnetic anisotropy and magnetization effects on reversal mechanisms. The single-phased Fe-Cr films have a bcc structure with 110 preferred orientation. Since the magnetization decreases as the Fe content is decreased and the uniaxial anisotropy energy keeps at al...

Effect of addition of municipal solid waste compost (MSWC) on chromium (Cr) content of submerged rice paddies was studied. Experiments were conducted during the three consecutive wet seasons from 1997 to 1999 on rice grown under submergence, at the Experimental Farm of Calcutta University, India. A sequential extraction method was used to determine the various chromium fractions in MSWC and cow...

We measured the low temperature specific heat of a sputtered (Fe 23Å /Cr 12Å )33 magnetic multilayer, as well as separate 1000 Å thick Fe and Cr films. Magnetoresistance and magnetization measurements on the multilayer demonstrated antiparallel coupling between the Fe layers. Using microcalorimeters made in our group, we measured the specific heat for 4 < T < 30 K and in magnetic fields up to 8...

We have used X-Ray Magnetic Circular Dichroism (XMCD) and magnetometry to study isolated Fe@Cr core-shell nanoparticles with an Fe core diameter of 2.7 nm (850 atoms) and a Cr shell thickness varying between 1 and 2 monolayers. The addition of Cr shells significantly reduces the spin moment but does not change the orbital moment. At least two Cr atomic layers are required to stabilize a ferroma...

Fe-based coatings with high V and Cr content were obtained by laser cladding using Fe-based powder with different Cr3C2 and FeV50 content. The results showed that Fe-based coatings were uniform and dense. The constituent phases were mainly composed of α-Fe solid solution with the increase of Cr3C2 and FeV50, γ-Fe and V8C7 phases were achieved. The microstructure of the coatings exhibited a typi...

Background: Metal-organic frameworks (MOFs) represent tremendous potential as heterogeneous catalyst in renewable energy production. In this study, biodiesel production using the modified MOF nanocatalyst was investigated esterification reaction. Methods: prepared solvothermal method and through sulfation process. The nanocatalysts characterized by XRD, FT-IR, FE-SEM, TEM, N2 adsorption-desorpt...

A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resu...