Texte 27. "Afin que l’argent des déposants auprès des sociétés de placement ne se perde pas."

al-Husawwar, n°3238, 31/10/86 Les signes avant-coureurs de la catastrophe sont déjà apparus lorsque le -propriétaire de l’une de ces sociétés a réuni des millions et s’est enfui à l’étranger, laissant les déposants frustrés des fonds qu’ils avaient économisés toute leur vie durant. On peut aussi citer le cas de cet autre qui ayant également réuni des millions, a par la suite été déclaré en faillite. Il passe deux années en prison, mais que dire des fonds des déposants qui sont perdus ? Et que..

Catalytic decomposition of methane to COx-free hydrogen and carbon nanotubes over Co–W/MgO catalysts

Bimetallic catalysts containing a series of Co/W at 40/10, 30/20, 20/30 and 10/40 wt% supported on MgO with a total metal content of 50 wt% were prepared and used for the catalytic decomposition of methane to COx-free hydrogen and multi-walled carbon nanotubes (MWCNTs). The solid fresh and exhausted catalysts were characterized structurally and chemically through XRD, TPR, BET, TGA, TEM and Raman spectroscopy. The 40%Co–10%W/MgO catalyst exhibited the highest activity for the production of both hydrogen and MWCNTs. The formation of a large amount of non-interacted Co3O4 species is considered as the main reason for the catalyst superiority in its activity. On the contrary, catalysts formulations of 20%Co–30%W and 10%Co–40%W demonstrated the formation of a large amount of hardly reducible CoWO4 and MgWO4 particles causing lower activity of these catalysts toward methane decomposition as evidenced through the XRD and TPR results

Correlation between the distance of maxillary central incisors and incisive papilla in different arch form

In edentulous treatment, relocation of anterior teeth in the preexisting natural position is the utmost importance. It is necessary to refer to the significant anatomical landmarks, one of them is incisive papilla. To make it more efficient both functionally and biologically, the teeth were arranged in particular geometric manner known as a dental arch. The author has chosen to conducted the research among the Malay race represented by the Malay undergraduate students. The purpose of this study was to evaluate the correlation between the distance of maxillary central incisors and incisive papilla (CI-IP) in different arch form and gender. Maxillary impressions of 34 dentate individuals were taken, and the measurements were performed using a digital caliper. The results showed the CI-IP distance was ranging between 7.65 to 9.90 mm, with the average of 8.77 mm. There was no significant difference of the CI-IP distance between male and female regardless of their arch forms (p>0.05). Individuals with ovoid and tapered arch form, however, showed a significant difference of the CI-IP distance between male and female (p0.05). It can be concluded that gender factor was irrelevant towards the CI-IP distance regardless of the individual arch form. However, there was a correlation between the CI-IP distance in different arch forms in both male and female sample

Catalytic para-xylene maximization. Part X: Toluene disproportionation on HF promoted H-ZSM-5 catalysts

H-ZSM-5 zeolite catalysts were doped with 2%, 3% and 4%HF to be used for investigating their activities and selectivities for xylenes production and for para-xylene maximization at temperatures of 300–500 °C via toluene disproportionation. This doping caused pore size modification of the H-ZSM-5 catalyst. The reaction was carried out in a fixed bed flow type reactor. The ratio of produced para-xylene relative to its thermodynamic composition reached as high as 3.29 at 300 °C on the 4%HF doped H-ZSM-5 catalyst although this catalyst possessed the lowest amount of the largest pores (3.0–5.7 nm) and the smallest pores (0.4–1.7 nm). The overall activities of the catalysts were decreased with an increase in HF doping because of diffusion restriction. The kinetics of the reaction were simply treated and found to give Ea and ΔS∗ values compatible with the characterization data of the catalysts

Catalytic Decomposition of Natural Gas to CO/CO2-Free Hydrogen Production and Carbon Nanomaterials Using MgO-Supported Monometallic Iron Family Catalysts

Monometallic Fe, Co, and Ni/MgO catalysts with 50 wt.% metal loadings were prepared and examined for natural gas decomposition to nanocarbonaceous materials, particularly multiwalled carbon nanotubes (MWCNTs) and co-valuable hydrogen. The catalytic testing was carried out in a fixed-bed horizontal reactor at 700°C under atmospheric pressure. The fresh and/or used catalysts were characterized using XRD, TPR, HRTEM, SEM, TG/DTA, Raman spectroscopy, and BET surface measurements. The resulting data showed that the 50%Co/MgO catalyst displayed higher catalytic decomposition activity of natural gas to CO x -free hydrogen production (∼88%), higher yield of MWCNTs, and excellent stability up to 10 h time-on-stream. On the other hand, the Ni-containing catalyst showed lower catalytic activity toward hydrogen and CNTs production, principally due to the formation of rock-salt Mg x Ni (1-x) O solid solution as observed from XRD and TPR data. Accordingly, the concentration of Ni particles required for natural gas feed was extremely low. The d orbital of Ni was presumed to be occupied during the formation of the solid solution, which inhibits the solublization or adsorption of hydrocarbons on Ni particles. The MWCNTs obtained over Ni-based catalyst had narrow and homogeneous diameters (∼11-13 nm). However, the Fe/MgO catalyst exhibited intermediate activity between those of Ni and Co˭MgO catalysts toward hydrogen production (∼44%). This catalyst produced mixtures of carbon nanofibers and nanotubes

Direct conversion of natural gas into COx-free hydrogen and MWCNTs over commercial Ni–Mo/Al2O3 catalyst: Effect of reaction parameters

A commercial hydrotreating nickel molybdate/alumina catalyst was used for the direct conversion of natural gas (NG) into COx-free hydrogen and a co-valuable product of multi-walled carbon nanotubes (MWCNTs). The catalytic runs were carried out atmospherically in a fixed-bed flow reactor. The effect of reaction temperature between 600 and 800 °C, and dilution of the NG feed with nitrogen as well as pretreatment of the catalyst with hydrogen were investigated. At a reaction temperature of 700 °C and dilution ratio of NG/N2 = 20/30, the optimum yield of H2 (∼80%) was obtained with higher longevity. However, using the feed ratio of NG/N2 = 30/20, the optimum yield of MWCNTs was obtained (669%). X-ray diffraction pattern for the catalyst after the reaction showed that the MWCNTs were grown on the catalyst at all reaction temperatures under study. TEM pictures revealed that the as-grown MWCNTs at 600, 650 and 800 °C are short and long with a low graphitization degree. At 700 °C a forest of condensed CNTs is formed, whereas both carbon nanofibers and CNTs were formed at 750 °C