Wall Rock Alteration,Uranium Mineralization,and Potentiality of Uranium and Iron Dissolution from Mineralized Abu Rusheid Gneiss Rock,South Eastern Desert,Egypt

Radiochemistry - Ferrugination, sericitization, desulfitization, chloritization, and kaolinitization of hydrothermal origin are the main wall rock alterations occurring within the NNW shear zones...     

International immigration and domestic out-migrants: are domestic migrants moving to new jobs or away from immigrants?

Domestic migrant responses to geographically concentrated immigration flows play central roles in determining the local economic impacts of immigration and the geography of the ethnic composition of the population. Possible motivations for domestic migrant responses include: increased labor market competition associated with new immigrants and ethnic or cultural avoidance. We use US annual state-to-state migration flows from the Internal Revenue Service to assess the existence and nature of the link between geographically concentrated immigration and domestic migration. We find some evidence of a domestic migrant response to immigrants, particularly to greater cumulative shares of the foreign born, which we interpret as providing some support of the ethnic or cultural avoidance hypothesis.     

On the formation of blisters in annealed hydrogenated a-Si layers

Differently hydrogenated radio frequency-sputtered a-Si layers have been studied by infrared (IR) spectroscopy as a function of the annealing time at 350°C with the aim to get a deeper understanding of the origin of blisters previously observed by us in a-Si/a-Ge multilayers prepared under the same conditions as the ones applied to the present a-Si layers. The H content varied between 10.8 and 17.6 at.% as measured by elastic recoil detection analysis. IR spectroscopy showed that the concentration of the clustered (Si-H)_n groups and of the (Si-H₂)_n (n ≥ 1) polymers increased at the expense of the Si-H mono-hydrides with increasing annealing time, suggesting that there is a corresponding increase of the volume of micro-voids whose walls are assumed from literature to be decorated by the clustered mono-hydride groups and polymers. At the same time, an increase in the size of surface blisters was observed. Also, with increasing annealing time, the total concentration of bonded H of any type decreases, indicating that H is partially released from its bonds to Si. It is argued that the H released from the (Si-H)_n complexes and polymers at the microvoid surfaces form molecular H₂ inside the voids, whose size increases upon annealing because of the thermal expansion of the H₂ gas, eventually producing plastic surface deformation in the shape of blisters.     

Optical spectroscopy on monomeric and polymeric 1:1 fulleride salts

We compare infrared spectra of the C ₆₀ ^– monoanion in different solid-state structures with each other as well with that of the neutral molecule. We relate the shift and splitting of theT _c infrared modes to the strength and anisotropy of electron-phonon coupling in those environments.     

Interactions and Chemical Transformations of Coronene Inside and Outside Carbon Nanotubes

By exposing flat and curved carbon surfaces to coronene, a variety of van der Waals hybrid heterostructures are prepared, including coronene encapsulated in carbon nanotubes, and coronene and dicoronylene adsorbed on nanotubes or graphite via π–π interactions. The structure of the final product is determined by the temperature of the experiment and the curvature of the carbon surface. While at temperatures below and close to the sublimation point of coronene, nanotubes with suitable diameters are filled with single coronene molecules, at higher temperatures additional dimerization and oligomerization of coronene occurs on the surface of carbon nanotubes. The fact that dicoronylene and possible higher oligomers are formed at lower temperatures than expected for vapor‐phase polymerization indicates the active role of the carbon surface used primarily as template. Removal of adsorbed species from the nanotube surface is of utmost importance for reliable characterization of encapsulated molecules: it is demonstrated that the green fluorescence attributed previously to encapsulated coronene is instead caused by dicoronylene adsorbed on the surface which can be solubilized and removed using surfactants. After removing most of the adsorbed layer, a combination of Raman spectroscopy and transmission electron microscopy was employed to follow the transformation dynamics of coronene molecules inside nanotubes.     

Bio-fouling in membrane processes: micro-organism/surface interactions, hydrodynamic detachment method

Bio-fouling is the principal problem met with membrane filtration in biological suspensions treatment, in particular in the case of membranes made of sintered clay which have a low resistance to chemical washing; we are interesting, in this work, to the bioadhesion which is the cause. At first, by the characterization of the particle/surface interactions; and then, by the study of a hydrodynamic detachment technique which could allow the break up of this bioadhesion and, thus, the membrane die-fouling. The results of the experimental study using the specially designed shear stress flow chamber show that micro-organism/support adhesion can be broken by the only effect of this force, and that the recourse to the chemical attack is not necessary. We, therefore, recommended luting against the biofilm fouling a hydrodynamic washing method by the application of a shear stress. And consequently, the ceramic membranes with low resistance to chemical washing would be adequate for the use in a bioreactor thanks to the adaptation of this technique.     

Conjugate pair fast Fourier transform

A new algorithm for the fast computation of the discrete Fourier transform is introduced. The algorithm, called the conjugate pair FFT (CPFFT), is used to compute a length-2/sup n/ DFT. The number of multiplications and additions required by the CPFFT is less than that required by the SRFFT algorithm.<>