Mass Spectrometry of Metalloporphyrins in Egyptian Oil Shales from Red Sea Area

Abstract

Metalloporphyrins, extracted from asphaltene and maltene fractions of some Egyptian oil shales (Abu-Shegeili, El-Beida, El-Nakheil, and Abu-Tundub in the Red Sea area) by means of adsorption column chromatography and TLC, were subjected to mass spectrometry in order to elucidate the structure of different types of VO, Ni, or Fe porphyrins. Metalloporphyrins were not detected in maltene or asphaltene fractions of Abu-Shegeili oil shale. The mass spectra appeared as a truncated series of mass numbers, which is characteristic of geo-porphyrins in sediments or oil shales. The data indicated that the five types of porphyrins (Etio, DPEP, BEtio, BDPEP, and THBD) with carbon numbers ranging from C₂₀ to C₅₀ were present in considerable detection levels. Based on mass spectrometric data, the major components of metalloporphyrins (VO, Ni, or Fe) were identified and their chemical structures were suggested. The occurrence and distribution of VO, Ni, and Fe porphyrins were interpreted from a geochemical point of view, particularly maturation levels and oil-gas potentials of kerogens.     

Structural,morphological and electrical properties of Cr2O3 nanoparticles

Chromium oxide (Cr₂O₃) nanoparticles have been prepared by chemical precipitation followed by calcination at high temperatures. The influence of calcination temperature on the particle size, microstructure, surface area and morphology was examined by X-ray diffraction, Fourier transform infrared, N₂ adsorption–desorption isotherms, transmission electron microscopy and thermal analysis techniques. The results indicate the formation of a nanosized single Cr₂O₃ phase. The particles possess high specific surface area and mesoporous structure, and their sizes increase with increasing the calcinations temperature. DC conductivity was measured in the temperatures range of 170–475 K. For the high temperature region, the conduction was found to be due to small polaron hopping of holes. While for the low temperatures region, the conduction was attributed to variable range hopping mechanism of holes. The temperature dependence of the AC conductivity and dielectric constant was investigated in the same temperature range at four test frequencies. In addition, the impedance spectra of these nanoparticles were investigated only at temperatures above 350 K.     

Prediction of sediment inflows to Angereb dam reservoir using the SRH‐1D sediment transport model

Angereb Dam, located in Ethiopia, was constructed in early 1994 as a water supply for the town of Gondar up to the year 2020. The reservoir could not achieve this objective, however, because of significant sedimentation problems. Accordingly, one objective of this study was to simulate the historical reservoir sedimentation pattern, as well as predict the near future (until 2015) sedimentation pattern of Angereb Reservoir. The Sedimentation and River Hydraulics one‐dimensional model (SRH‐1D), version 2.6, was used for this purpose. Another objective was to propose possible mitigation measures to reduce the quantity and rate of sedimentation in the reservoir. There was generally good agreement between measurements and model simulations, with the observed trends being well simulated. The exception was that the model tended to overpredict the sediment deposition volumes in the upstream reaches of the reservoir. The two mitigation alternatives for addressing the sedimentation problem, namely managing sediments in the watershed and flushing sediment through the dam bottom outlet, appear to be technically feasibility, with a predicted reduction of the volume of deposited sediment between 63 and 80% be achievable.     

Analysis of Neutronic Parameters for Supercell of CANDU Reactor Using MCNPX Code

MCNPX code has been used for modeling and simulation of a supercell of CANDU Fuel, the supercell consists of two fuel bundle and adjuster rod. The fuel bundle are burnt in normal operation conditions of CANDU reactors. Natural uranium fuel is used in the model. The multiplication factor of the bundle is calculated during fuel burnup. The concentration of both uranium and plutonium isotopes are analysed in the bundle. The worth of the adjuster rod is calculated. Comparison of multiplication factor and worth of the adjuster rod with the previous published references showed good agreement.     

Homogeneous Styrene Butadiene/Acrylonitrile Butadiene Rubber Blends

The graft copolymerization of acrylonitrile (AN) onto butadiene rubber (BR) was carried out in toluene at 80°C, using dibenzoyl-peroxide (BPO) as initiator. The synthesized poly acrylonitrile-grafted-butadiene rubber (AN-g-BR) was characterized by N% elemental analysis and Fourier-transform infrared (FT-IR) spectroscopy. Styrene butadiene rubber/acrylonitrile butadiene rubber (SBR/NBR) blends were prepared with different blend ratios in presence and absence of AN-g-BR, where the homogeneity of such blends were examined with intrinsic viscosity (η) measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The scanning electron micrographs illustrate disappearance of the macro-scale phase separation of SBR/NBR rubber blend as a result of the incorporation of AN-g-BR into that blend. Viscosity measurements confirm homogeneity of that blend. Differential Scanning Calorimetry traces exhibit shifts in glass transition temperatures (T _g's) of SBR and NBR in their blend, indicating some degree of homogeneity. Physico-mechanical properties of the rubber blend vulcanizates with different blend ratios, in presence and absence of AN-g-BR, were investigated before and after accelerated thermal aging. The SBR/NBR (25/75) homogeneous blend possessed the best physico-mechanical properties after thermal aging, together with the best swelling behavior in motor oil. The physico-mechanical properties of SBR/NBR (25/75) filled blend with different types of inorganic fillers during thermal aging were studied.     

Analysis of Polycyclic Aromatic Hydrocarbons in Egyptian Petroleum Condensate Oils

The polycyclic aromatic hydrocarbons (PAH) in Egyptian condensates are analyzed for the first. A solid phase extraction (SPE) followed by gas chromatography-mass selective detection was used for their analysis. The method was calibrated for optimal extraction conditions. Excellent recoveries were found (78–114%) for the PAHs that were identified using a variety of standards and GC-MS spectra. The solid-phase extracted PAH fraction was further separated by HPLC on a Ag(I) mercaptopropanosilica gel to reduce the complexity of the sample by separating the PAHs based on the number of aromatic rings. The analytes were quantified using GC with a flame ionization detector. For this kind of sample SPE is a more convenient separation technique than an open column. PAHs containing two to four rings in the concentration range 0.6–11 μg/L were measured. Some preliminary geochemical hypotheses based on the analyzed PAHs and the previously analyzed S-containing aromatic compounds were formed as to the depositional environment and source rock type.     

Investigation of Crystal Structure,Electrical and Magnetic Properties of Spinel Mn-Cd Ferrite Nanoparticles

Journal of Inorganic and Organometallic Polymers and Materials - Cd1 ? xMnxFe2O4 (x?=?0, 0.25, 0.5, 0.75, 1) spinel ferrite nanoparticle samples were synthesized...     

Specific cationic photoinitiators for near UV and visible LEDs: Iodonium versus ferrocenium structures

Two iodonium salts based on a coumarin chromophore are investigated for polymerization upon light emitting diode irradiations (LEDs). They work as one‐component photoinitiators. They initiate the cationic polymerization of epoxides (under air) and vinylethers (laminate) upon exposure to violet LEDs (385 and 405 nm). Excellent polymerization profiles are recorded. Their efficiency is quite similar to that of a ferrocenium salt. Interpenetrating polymer networks can also be obtained through a concomitant cationic/radical photopolymerization of an epoxy/acrylate blend monomer. The light absorption properties of these new salts as well as the involved photochemical mechanisms are investigated for the first time through electron spin resonance, laser flash photolysis, steady state photolysis experiments. Molecular orbital calculations are also used to shed some light on the initiation mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42759.     

Pickering Emulsion Polymerization of Styrene using Nano-SiO2 and Subsequent Use of the Produced Core–Shell Structures as Fillers for Ethylene Vinyl Acetate Copolymer and Polypropylene

Solid particles can stabilize emulsions instead of conventional surfactants. Emulsion polymerization of styrene, as an example of polymerizable oil, was processed in the present work after ultrasonication of styrene in water in the presence of silica nanoparticles as stabilizer. Field emission scanning electron microscopy, equipped with energy-dispersive X-ray unit, and transmission electron microscopy confirmed the formation of polystyrene particles covered by a sheath of self-assembled silica. Addition of these hybrids in different loadings (2–14 wt%) to polypropylene and ethylene vinyl acetate copolymer could improve their tensile strength and hardness. The mechanical enrichment could be attributed to the action of the silica shell layer to delay the phase separation process encountered between the polystyrene from one side and polypropylene/ethylene vinyl acetate from other side, which translates into different extents of reinforcements.