SUPERCRITICAL EXTRACTION OF ORGANOSULFUR FROM COAL USING ACETONE-VATER MIXTURES

Abstract

Binary mixtures of acetone and water at their supercritical conditions have been investigated for their ability to remove organic sulfur from high sulfur Midwestern coals. The reduction of organic sulfur from Ohio 5/6 and Indiana 5 coals has been as high as 61% (based on a BTU basis) The experiments have been carried out following a statistical experimental design and the optimal process conditions and discerning characteristics of the process have been identified. The solvent composition and the extraction conditions can be tailored in such a way as to selectively remove sulfur and further increase the calorific value of the treated coal.     

A Comparison between Porosity Derived from Seismic Reflection Data and That Computed from Well Log Data,Al Amal Field,Gulf of Suez,Egypt

Abstract

The present study is a trial to predict of porosity from seismic data in the Al-Amal field, Gulf of Suez, Egypt. This is carried out through the inversion of seismic traces, which allows estimation of reservoir porosity from the analysis of transit times derived from pseudo-velocity logs. A four-step computational procedure is illustrated starting with the inversion of seismic traces and calculation of interval velocities; accurate stratigraphic interpretation; determination of the petrophysical parameters for the porosity evaluation; and analysis of the reliability of the results and final corrections.     

Strength of soil reinforced with fiber materials (Papyrus)

Construction of building and other civil engineering structures on weak or soft soil is highly risky because such soil is susceptible to differential settlements, poor shear strength, and high compressibility. Various soil improvement techniques have been used to enhance the engineering properties of soil. Soil reinforcement by fiber material is considered an effective ground improvement method because of its cost effectiveness, easy adaptability, and reproducibility. Hence, in the present investigation, papyrus fiber has been chosen as the reinforcement material, and it was randomly included into the soil at four different percentages of fiber content, i.e., 5, 10, 15, 25% by volume of raw soil. The main objective of this research is to focus on the strength behavior of soil reinforced with randomly included papyrus fiber. Direct shear, consolidation, and displacement tests were performed on papyrusreinforced specimens with various fiber contents. The results of these tests have clearly shown a significant improvement in the failure deviator stress and shear strength parameters (c and φ) of the studied soil with a percent addition of 10% (the preferred percent). Moreover, this addition ratio reduced the displacement of the soil under loading. It can be concluded that papyrus fiber can be considered an appropriate soil reinforcement material.     

Undrained shear strength of clays as modified by pH variations

The undrained shear strength of clays is an important geotechnical parameter used during construction processes. Several laboratory tests were performed on kaolinite and smectite mixed with pore fluids with different pH values. Vane shear tests were carried out and it was found that the undrained shear resistance for clays increased considerably if the pore fluid had a high or a low pH. A possible explanation could be the dissolution of Al³⁺ which acts as a coagulant, increasing the internal shear resistance. Geochemical computations, Al measurements and ζ-potential experiments were performed to confirm this theory. The research suggests varying the pH may make a useful contribution to soil improvement techniques.     

Improved mechanical and tribological properties of A356 reinforced by MWCNTs

The objective of this paper is to investigate the effect of Multi-Walled Carbon Nanotubes (MWCNTs) content on microstructure and dry sliding wear behavior of hypo-eutectic A356Al–Si alloy Metal Matrix Nano-Composites (MMNCs). Composites containing 0.5, 1.5, and 2.5 wt.% MWCNTs were prepared by rheocasting technique followed by squeeze casting. Characterization of nanocomposites was done by scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX), dry sliding wear tests were performed in a pin-on-disk wear tester against a steel disk at various speeds and normal loads. Results revealed that a decrease in both wear rate and friction coefficient of the nanocomposites considerably with the increase of MWCNT's content. The formation of the hard compact transfer layer on the pin surface nanocomposites assisted in increasing the wear resistance of these materials. It is that the transfer layer which was formed under an applied load of 20 N can act as a protective layer and help in reducing the wear rate. The results indicate the nano composites could be used in light-weight applications where moderate strength and wear properties are needed.     

Einfluss der Korngrößenverteilungen nichtbindiger homogener Böden auf hydraulischen Grundbruch

Grundwasser - Die vorliegende Arbeit beschäftigt sich mit dem Einfluss der Korngrößenverteilungen von nichtbindigen homogenen Böden auf den Mechanismus des hydraulischen...     

Synthesis and characterization of N-alkyl-2-aminopyridinum oligomers as pour point depressants for crude oil

The synthesis of N-decyl- (C10P), N-dodecyl- (C12P) and N-cetyl-2-aminopyridinum (C16P) oligomers was achieved by oxidative polymerization of N-decyl- (C₁₀), N-dodecyl- (C₁₂) and N-cetyl-2-aminopyridinium bromide monomers respectively in aqueous acid medium. Density function theory (DFT) was applied to recognize the reactive center in monomers used. The result of quantum calculations indicated that the oligomerization could proceed via open ring reaction. The obtained oligomers were characterized using FTIR and ¹H NMR spectroscopy. In addition, the XRD and SEM were used to investigate the morphology of the prepared oligomers. The thermal stability of the obtained oligomers was followed by thermogravimetric analysis (TGA). The conversion of these oligomers is ranged from 61 to 68% and the weight average molecular weights are closed to 3000?g?mol^?1. The surface tension of the synthesized oligomers was measured at different concentrations and temperatures. The efficiency of the synthesized oligomers in depressing the pour point of crude oil was investigated. The synthesized oligomers showed high efficiency as pour point dispersants.     

Infrared broadband 50%-50% beam splitters for s-polarized light

Prisms and slabs made of high-refractive-index materials such as ZnSe, Ge, and Si can be designed as broadband, 50%-50%, beam splitters (BSs) for obliquely incident s- polarized light in the near- and mid-IR. The beam-splitting face of the prism or slab is uncoated, while the exit face is antireflection coated. The split beams travel in orthogonal directions when light is incident at the Brewster angle. A novel design is also described that uses Brewster-angle reflection at the SiO2-Si interface to achieve a 50%-50%s-polarization BS over the 1.2-3.5 microm spectral range. Such s-polarization BSs are particularly suited for interferometry and holography.     

Parametric studies on the CO2 laser cutting of Kevlar-49 composite

In the present study, the cutting performance of a CO₂ laser on Kevlar-49 composite materials has been studied. The Taguchi technique is employed to identify the effect of laser control parameters, i.e., laser power, cutting speed, material thickness, assistance gas pressure, and laser mode, on the quality of cut parameters, namely, kerf width, dross height, and slope of the cut. From the analysis of variance (ANOVA) and signal-to-noise (S/N) ratio response tables, the significant parameters and the optimal combination levels of cutting parameters are determined. The obtained results are interpreted and modeled to closely understand the behavior and quality of CO₂ laser cutting. Kevlar-49 composites are found to be cut satisfactorily by the CO₂ laser at the optimum process parameter ranges. The results showed that laser power is the most significant parameter affecting the quality of cut parameters. The optimal combination of cutting parameters minimized the kerf width, dross height, and slope of cut to 0.103 mm, 0.101 mm, and 2.06°, respectively. The error between experimental results with optimum settings and the predicted values for the kerf width, dross height, and slope of cut lie within 2.9%, 7.92%, and 6.3%, respectively.