Volume 2 Issue 3
Authors: N. N.V.Rozhanskii; V. V.L.Goncharov; Yu. V.Lakhotkin; V. V.P.Kuzmin; V. V. Dushik
Abstract: The paper reports on the study of carbon nanocrystals formed in the process of low-temperature CVD synthesis of tungsten carbide coatings in WF6, C3H8, H2 gas reagents. The morphology and structure of observed nanocrystals were studied by the method of transmission electron microscopy. Carbon nanoparticles and nanotubes (sometimes filled by Ni or iron fluorides) were found in deposits formed on Ni or stainless steel substrates. In the latter case nanocrystalline whiskers of cubic carbon (Pm3m) were also observed.
Keywords: Carbon Nanotubes; Carbon Nanoparticles; CVD; TEM
Authors: Benjaram M. Reddy; Padigapati S. Reddy; Baithy Mallesham; Putla Sudarsanam
Abstract: Esterification of biodiesel–derived glycerol with acetic acid was investigated over Al2O3–ZrO2, CeO2–ZrO2, SO42–/Al2O3–ZrO2 and SO42–/CeO2–ZrO2 solid acid catalysts. The obtained glycerol esters, namely mono–, di– and tri–acylglycerols are versatile chemicals to improve both physicochemical properties of biodiesel as well as its economic profitability. The prepared solid acids were characterized by means of XRD, BET surface area, and ammonia–TPD techniques. It was found that the addition of sulfate ions significantly enhances the surface acidity of mixed oxides. Interestingly, the SO42–/CeO2–ZrO2 solid acid showed higher amount of super acidic sites, whereas only medium and strong acidic sites were observed in the case of SO42–/Al2O3–ZrO2 sample. Among various catalysts investigated, the SO42–/CeO2–ZrO2 catalyst exhibited excellent catalytic activity (~100% glycerol conversion) with better reusability up to three catalytic runs. The results showed that promoted zirconia–based solid acids are the promising heterogeneous catalysts for esterification of glycerol.
Keywords: Biodiesel; Glycerol; Zirconia; Solid Acids; Esterification; Triacylglycerol
Authors: Weixue Xu; Dawei Wang; Jianguang Li; Ning Cao; Hong Shao
Abstract: A series of sodium bentonites as raw material were purified. The purification bentonite was used to prepare clay nanocomposite with the requirement of high montmorillonite content. The methylene blue absorbed and swelling volume were selected as two indexes. And the optimal purification conditions were measured: bentonite slurry concentration of 7%, stirring time of 20min, centrifugal time of 30min, none dispersant agent requested. Then the montmorillonite content reached as high as 98.66%. The grain size, structural characterization and morphology of the purification bentonites were observed by means of X-ray diffraction, scanning electron microscopy. A better dispersibility and higher content matrix of montmorillonite were obtained by the purification process of bentonite.
Keywords: Bentonite; Montmorillonite; Purification Process; XRD; SEM
Authors: A. S.Fouda; H. S.Gadow
Abstract: The corrosion behavior of carbon steel in HCl solution containing various concentrations of cyanoacetate and oxobutanoate derivatives was investigated. The corrosion inhibitive action of these compounds on carbon steel was studied using chemical and electrochemical methods. The results showed that the inhibition efficiency increases by increasing the concentration and decreases by increasing the temperature. The synergistic effect of potassium iodide (KI) in presence of various concentrations of these compounds was also investigated. Polarization curves revealed that these compounds are mixed type inhibitors. The adsorption of these compounds follows the kinetic thermodynamic model and Temkin adsorption isotherm. Some thermodynamic parameters of activation and adsorption processes were also determined and discussed.
Keywords: Carbon Steel; Corrosion Inhibition; HCl; Cyanoacetate and Oxobutanoate Derivatives
Authors: Salwa M. Al-Thawadi
Abstract: BioCementation technology depends on the consolidation of sand particles by using pure microorganisms (B. pasteurii) under complete sterilization conditions during the cellular growth. In this study, an enrichment culture of ureolytic bacteria was used to precipitate aggregates of calcite in-situ under non-sterile conditions. Those bacteria were enriched in the presence of 3 M urea. Soil sample was collected from agricultural fields in Sakhir, Bahrain. Then they were used to precipitate calcite in-situ and consolidate sand particles in the presence of high concentration of 1 M equimolar urea and calcium ions. Continuous feeding of cells was applied. Optical microscope, SEM, EDS, XRD and XRF examinations revealed that this impure bacterial culture resulted in precipitating aggregates of calcite nanoparticles in spherical arrangement in-situ which consolidate packed sand column. Natural competence between bacteria in the enrichment culture did not affect their ability to precipitate calcite nanoparticles and strengthen the sand without interfering with the hydraulics of the treated sand. Therefore, cost of BioCementation technology can be lowered due to the enrichment of local bacteria under non-sterile conditions.
Keywords: Biocementation; Calcite Nanoparticles; Ureolytic Bacteria; Urease; Sandstones
Authors: Sadek AWAD
Abstract: The stable isotope of the carbon atom (13C) gives information about the type of the mineralization of the groundwater existing during the water seepage and about the recharge conditions of the groundwater. The concentration of the CO2(aq.) dissolved during the infiltration of the water through the soil’s layers has effect on the mineralization of the water. The type of the photosynthesis’s cycle (C-3 or C-4 carbon cycle) can play a very important role in determining the conditions (closed or open system) of the mineralization of groundwater. The isotope 13C of the dissolved CO2 in water gives us certain information about the origin and the area of pollution of water. The proportion of the biogenic carbon and its percentage in the mineralization of groundwater are determined by using the isotope 13C.
Keywords: Isotopes; Carbon-13; Mineralization; Pollution; Bekaa; Lebanon
Authors: Yasuo Iwaki
Abstract: The main purpose of paper argues for the assurance-based on data result of low-concentration chemical analysis. The data of high Quality Accuracy (QA) are needed in many fields, especially, radio-biochemistry and environmental chemistry. QA of chemical analysis result needs to be maintaining reliance and an assurance for quality management. Reliability is based on the transparency of information and execution of social responsibility by ISO 26000. The many international organs and agency have promoted making the rules for QA. Representation rule is protocol of MARLAP by EPA and it is recommended by IAEA and ICRP. Safety and reliance needs the sustainability management with high quality control level. The improvement technology of QA utilizes traceability by Quality Engineering (QE) and standardization by ISO-GUM for quality accuracy. Since the factor of uncertainty influences, it should be careful of especially the Biochemical analysis of very low concentration.
Keywords: ISO-GUM; MARLAP; Uncertainty; Chemical; Analysis; Low Concentration; MCMC; QA
Authors: Junda Zhu; David He; Eric Bechhoefer
Abstract: Recently, an increasing demand for performance assessment of lubrication oil has been noticed. Considerable techniques and systems in lubrication oil condition monitoring have been developed and successfully utilized in many applications such as gasoline/diesel engines, gearboxes, etc. This paper provides a comprehensive review of the existing lubrication oil condition monitoring solutions and their characteristics along with the classification and evaluation of each technique. The reviewed techniques are analyzed and classified into four categories: electrical (magnetic), physical, chemical, and optical techniques. The characteristic of each solution and its sensing technique is evaluated with a set of properties which are crucial for oil health monitoring, diagnostics and prognostics. A comprehensive comparison among a wide range of different lubrication oil condition monitoring solutions is conducted.
Keywords: Lubrication Oil; Performance Assessment; Condition Monitoring; Diagnostics; Prognostics